Auto Mechanic Servicing Hints


Find many automotive Repair recommendation and Auto Repair Help Tips. from the list bellow that will help you become more advance and expert auto mechanic in troubleshooting engine, chassis and automotive systems problems




  • If there is a crack in dust boots of the constant velocity joint, the grease will deteriorate and flow out, which will cause abnormal sounds and make it impossible to drive. Since there are various types of boot clamps that hold the drive shaft boots, refer to the Repair Manual and handle them correctly. The type and amount of grease used inside the drive shaft boots varies depending on the model, so refer to the Repair Manual.
  • Before disassembling the center bearing, match marks must be made on the flange yoke and intermediate shaft to ensure accuracy when the flange yoke is assembled after servicing. If parts are assembled without reference to the match marks, vibration and/or noise may result when the vehicle is driven
  • When removing and installing the propeller shaft: Since there is a shaft length adjusting mechanism, the adjusting nut should be loosened first before removing the propeller shaft. The bolts inserted in the propeller shaft companion flange should not be removed. Be careful not to apply undue force to the flexible couplings when handling the propeller shaft, and make sure the transmission, propeller shaft, and differential are always straight when removing and reinstalling the propeller shaft. After installation, be sure to check the joint angles.

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  • If air is mixed into the fluid line, air is pressurized and sufficient amount of oil pressure is not generated. Then, it causes poor clutching or the gears unable to shift.
  • Wear of the torsion rubber and breakage of the cushion plate causes a large amount of impact shock and noise when the clutch is engaged.

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  • Vibration Tire vibration problems are divided into body shake, steering flutter, and steering shimmy. Body shake is defined as vertical or lateral vibration of the vehicle body and steering wheel, along with vibration of the seats. Shimmy and flutter are defined as vibration in the steering wheel in its rotational direction.
  • Do not use a tire with a worn tread. As the tire wears, the tread reaches a point where the tread grooves cannot drain off the water between the tire and the road fast enough to prevent hydroplaning.
  • Raise the inflation pressure. A higher tire inflation pressure opposes the pressure of the water trying to force itself under the tread and thus delays the onset of hydroplaning.

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  • If the inner circumference of the synchronized ring and the speed gear cone portion become worn, both speeds cannot be in sync. Abnormal noise occurs or it becomes difficult to shift gears.
  • If the hub sleeve spline chamfer portion is worn, the transaxle jumps out of gear.
  • The drive shaft and axle shaft combination is also called the drive shaft.
  • The operation of the differential works to apply the same torque to both the right and left wheels. So while this has the advantage of making driving through curves smooth, it has the disadvantage of reducing the drive force to both wheels when the drive force is reduced to one wheel.
  • Side bearing preload -The thrust load is received from the ring gear, so if the preload adjustment is poor, the side bearing taper roller will wear causing unstable rotation. To prevent this, the preload adjustment using the adjusting shim or adjusting nut is required.
  • Drive pinion preload (FR) – The thrust load is received from the ring gear, so if the preload adjustment is poor, the taper roller bearings on both ends of the drive pinion will wear causing unstable rotation. To prevent this, the preload adjustment using the adjusting shim or collapsible spacer is required.
  • Hypoid gear backlash (FR) – The ring gear generates a thrust load, which is received by the drive pinion, so if the backlash adjustment is poor, an excessive force will be applied, causing damage to the teeth of both gears and seizing. It is required to adjust the adjusting nut or adjusting shim, and adjust the backlash.
  • Hypoid gear tooth contact (FR) – The ring gear generates a thrust load, which is received by the drive pinion, so if the tooth contact adjustment is poor, an excessive force will be applied, causing damage to the teeth of both gears and seizing or noise to occur be generated. Not only the backlash, but also the mutual tooth contact must be adjusted with the adjusting washer.
  • When the transfer shift lever is in the “L” range position, the L4 position switch is on, so center differential lock control relay operates regardless of whether the differential lock switch is on or off, and the motor turns, causing the center differential to be locked.
  • Older models had a center differential control switch. When driving in the “Off” mode, the condition is the same as when the mechanical locking type is run with the differential lock switch OFF.
  • The overdrive main switch may also be called the overdrive OFF switch or the transaxle (transmission) control switch. The E-shift type can shift the gear up or down with the transaxle/transmission shift switch.
  • When the shift lever of an automatic transmission for a FR vehicle is in the “P” range, the parking lock pawl is engaged with the front or rear planetary ring gear, which is splined with the output shaft, preventing movement of the vehicle. However, on FR- based 4WD vehicles, the movement of the vehicle cannot be prevented if the transfer mechanism is in neutral, even if the automatic transmission is in “P”. For this reason, be sure to set the parking brake when parking.
  • The current ECU is an integration of the Engine ECU and ECT ECU, but previously it was separated.

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  • The turbine runner rotates with the transaxle input shaft when the vehicle is running with the shift lever position in the “D”, “2″, “L” or “R” range. However, it is stopped rotating when the vehicle is stopped. When the shift lever position is in the “P” or “N” range, the turbine runner rotates freely with the rotation of the pump impeller.
  • STALL TEST – This test is used to check the overall performance of the engine and transaxle (the clutches and brakes of the planetary gear unit). It is carried out by rendering the vehicle immovable, then measuring the engine rpm while shifting to the “D” or “R” range and depressing the accelerator pedal all the way.
  • When the stator cannot be locked, symptoms of acceleration failure occur due to the system being in the coupling range. On the other hand, when the stator cannot rotate freely, the system remains in converter range and the symptom occurs such the speed does not increase above a certain speed. Inspection of One-way Clutch
  • Under normal conditions when the vehicle starts off, the torque converter reaches the clutch point 2 to 3 seconds. However, if the load is heavy even while the vehicle is running at a medium or high speed, the torque converter may operate in the converter range.
  • When the brakes are released, even if the accelerator pedal is not depressed, the vehicle slowly starts to move. This is called creep phenomenon.

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  • When the brake band is being replaced with a new one during overhauling of an automatic transaxle, soak the new brake band for 15 minutes or longer in the ATF (Automatic Transaxle Fluid) before installation.
  • The number of brake and clutch discs and plates differs depending on the automatic transaxle model. Even in automatic transaxles of the same model, the number of discs may differ depending on the engine the transaxle is combined with.
  • When replacing brake and clutch discs with new discs, soak the new discs in the ATF for 15 minutes or longer before installation.
  • Gap Adjustment: If the gap is too small, it will cause brake drag. If the gap is too large, it will cause braking delay.
  • There are sensor type pad wear indicator brakes like that shown at the bottom left of the figure. When the sensor is worn down together with the disc brake pad, the sensor’s circuit is opened. The ECU detects the open circuit and warns the driver.
  • Fading
  • When the foot brakes are applied (without engine braking) constantly on a long downhill slope, etc., the lining and disc brake pads become extremely hot due to friction. The coefficient of friction of the lining and disc brake pad surfaces decreases as a result, and the brakes exert less stopping power even if the brake pedal is depressed with a great effort.
  • Parking Brake Lever Travel Adjustment Use the following work procedure to make the adjustment.

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1. Loosen the lock nut.

2. Turn the adjusting nut or adjusting hexagon until the parking brake lever or pedal travel is correct.

3. Tighten the lock nut.

  • Before adjusting the parking brake lever (or pedal) travel, make sure the parking brake shoe clearance has been adjusted.
  • The brake assist changeover solenoid valve is only used in vehicles equipped with BA.
  • Inspection method
  • When a pressure in power supply system is released, reaction force becomes heavy and stroke becomes shorter. The master cylinder brake booster consists of a brake booster portion, master cylinder portion, and regulator portion. These are positioned coaxially to achieve a simple and compact construction.

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  • If the battery is dead, it is possible to start the engine of manual transaxle vehicles by push-starting it, but with automatic transaxle vehicles, this is not possible. During push-starting, since the oil pump is not operating, the operating hydraulic pressure of the planetary gear unit is not generated. In other words, the power from the tires is not transmitted to the engine.

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  • Use the dipstick for fluid level inspection, making sure that the engine is running at an idle and that the ATF (Automatic Transaxle Fluid) is at normal operating temperature.
  • When towing an automatic transaxle vehicle, since the oil pump does not operate, the fluid lubrication inside the transaxle can be insufficient and there is a danger of the transaxle being seized. For this reason, the automatic transaxle vehicle should be towed at a low speed (no more than 30 km/h) and no more than 80 km at one time. As a better method, the automatic transaxle vehicle should be towed with its drive wheels lifted clear of the ground, or the drive or propeller shaft should be disconnected.

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  • There is types of shift solenoid valve that raises a spool to open the fluid passage when the signal is off and closes the fluid passage when the signal is on. Also, the shift solenoid valve has No.1 and No.2 while the linear solenoid valve has a SLT that is used instead of the throttle valve and a SLU to control the lock up, etc.
  • Some models eliminate the parking lock cable and control with a solenoid valve
  • If there is trouble, such as an open circuit, that causes the electricity to stop flowing to the ISCV, the valve is made to open at a set position by the force of the permanent magnet. This will maintain an idling speed of approx. 1,000 to 1,200 rpm.

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  • The overdrive main switch is sometimes also called the overdrive OFF switch or transaxle (transmission) control switch. With the gate type shift lever, the O/D can be canceled by operating the lever. There is no O/D OFF indicator light because a positioning light can be used to show the shift lever position.
  • The contacts of this switch are also used to turn on one of the shift lever position indicator light to inform the driver of the current position of the shift lever. In addition, the ECU controls so that the starter can be operated only while the shift lever is in the “P” or “N” ranges, and so that when the shift lever is in the “R” range, a reverse warning buzzer sounds and the backup light turns on. Signals sent to the ECU from the neutral start switch vary by models.
  • When a vehicle is driven, you can judge if the automatic transaxle is faulty or not by how well the shifting points conform to the automatic shift diagram.
  • When the coolant temperature is low, the transaxle does not shift up to O/D gear.
  • For line pressure control, some models use the throttle cable in the same manner as the full hydraulically-controlled automatic transaxle.
  • If the solenoid valve (SLT) fails, the inner valve will be fixed at the top (Hi side), so there will be a greater shock during shifting.
  • Hill climbing and descending is determined by comparing the actual acceleration calculated from the speed sensor signal with the standard acceleration stored in the ECUÅfs memory.
  • In some models, the “O/D OFF” indicator light blinks when the ECU detects a malfunction.When the O/D main switch is OFF, the “O/D OFF”indicator light will remain on in the event of a malfunction, but it will not blink.
  • The correction resistor,which is listed above, is not attached to the injector of 1ND-TV E/G. 3 types of injectors are adopted based on the difference of the injection volume, and the indentification numbers (A, B, C) are attached on the top of each injector.

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  • Measures to prevent wind-up: Asymmetrical leaf springs Wind-up is reduced by offsetting the rear axle so that it is located slightly forward of the center of the leaf spring. This also serves to reduce the up-down motion of the body during acceleration and deceleration.
  • Shock absorber location Wind-up can be reduced by mounting the shock absorbers away from the center of wind-up and by bias-mounting them. That is, by mounting one in front of and one behind the axle.
  • Cavitation: When the fluid flows at high speed within the shock absorber, the pressure will drop in some areas, forming air pockets or cavities in the fluid. This phenomenon is called cavitation. These cavities collapse when carried into regions of high pressure, resulting in great impact pressure. This will generate noise, cause pressure fluctuations, and can damage the shock absorber itself.
  • Aeration: Aeration is the mixing of air with shock absorber fluid. This can lead to noise, pressure fluctuations, and pressure loss.
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  • Measures to prevent wind-up:
  • Asymmetrical leaf springs Wind-up is reduced by offsetting the rear axle so that it is located slightly forward of the center of the leaf spring. This also serves to reduce the up-down motion of the body during acceleration and deceleration.
  • Shock absorber location Wind-up can be reduced by mounting the shock absorbers away from the center of wind-up and by bias-mounting them. That is, by mounting one in front of and one behind the axle.
  • Cavitation: When the fluid flows at high speed within the shock absorber, the pressure will drop in some areas, forming air pockets or cavities in the fluid. This phenomenon is called cavitation. These cavities collapse when carried into regions of high pressure, resulting in great impact pressure. This will generate noise, cause pressure fluctuations, and can damage the shock absorber itself.
  • Aeration: Aeration is the mixing of air with shock absorber fluid. This can lead to noise, pressure fluctuations, and pressure loss.
  • Method to cancel the vehicle height control: Before jacking up the vehicle or raising it on a hoist, make sure that the ignition switch is turned OFF.
  • If the vehicle must be raised with its engine running, jump terminals TD and EI of the TDCL or OPB and CG of the DLC3 (Data Link Connector 3) to stop the vehicle height control operation of the air suspension ECU.
  • For the vehicle with the height control ON/OFF switch, the switch is turned OFF.

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  • If the wheels are given excessive positive or negative camber, this causes uneven tire wear. If the wheels are given excessive negative camber, the tires wear quicker on the inside; if the wheels are given excessive positive camber, the tires wear quicker on the outside.
  • Cornering is always accompanied by centrifugal force, which tires to force the vehicle to turn in a larger arc than intended by the driver unless the vehicle can generate a sufficient counterforce – that is, centripetal force – to balance this. This centripetal force is generated by the deformation and side-slipping of the tread that occurs due to friction between the tire and the road surface. This called cornering force.
  • If the wheels are given excessive positive caster, the straight-line stability is improved, but cornering becomes difficult
  • In front engine, front-wheel-drive cars, the offset is generally kept small (zero or negative) to prevent the transmission to the steering wheel of shock from the tires generated during braking or by striking an obstruction, and to minimize the moment created around the steering axis by the driving force at the time of quick starting or acceleration.
  • If there is a difference between the steering angle on the left and right, there will also be a difference between the moments around the steering axis on the left and right during braking and the braking force will be greater on the side with the smaller steering angle. Also, any difference between the left and right offsets generates a difference in the drive reaction force (torque steer) on the left and right. In either case, a force acts that attempts to turn the vehicle.
  • If toe-in is excessive, the side slip force causes uneven wear of the tires. If toe-out is excessive, it is difficult to secure straight-line stability.
  • Side slip is the total distance that the left and right tires slip to the side while the vehicle is running. Both in the case of toe-in and negative camber, side slip occurs towards the outside.
  • If the turning radius is improper, the inside or outside tire slips sideways during cornering and smooth turning is not possible. This also generates uneven wear on the side slipping tire.
  • In the case of rack-and-pinion steering gear, the wheel angle is typically determined by the point at which the steering rack end makes contact with the steering rack housing. Consequently, there is usually no knuckle bolt. If the lengths of the left and right tie rod ends are different,
  • Since the impact absorbing steering column is constructed so that it will absorb shock in the axial direction, never attempt to hammer the steering main shaft when removing the steering wheel as the force may break the pins in the impact-absorbing mechanism. Always use the SST designed for removing the steering wheel safely.
  • Since the steering column is no longer usable after collapsing, it must be replaced with a new one.
  • In some automatic transaxle vehicles with the shift lock mechanism, the steering lock mechanism is not provided.
  • When the ignition key is in the ACC or ON position, the lock stopper and lock bar are pushed to the right by the cam of the camshaft. The lock release lever therefore falls into the groove in the lock stopper, preventing the lock stopper and lock bar from moving to the left, and thus preventing the steering wheel from being locked while the vehicle is being driven.
  • When the ignition key is turned from ON to ACC position (shutting off the engine), the lock release lever strikes against the left edge of the groove in the lock stopper, preventing the lock stopper and lock bar from moving to the left (and thus preventing the steering wheel from being locked).
  • When the ignition key is in the ACC position As long as the ignition key is not pushed in while the lock is in the ACC position, the push plate is pushed out by the cylinder rotor return spring. For the reason, the stopper plate protrudes out and strikes against the edge of the lock body, preventing the rotor and ignition key from being turned to the LOCK position.
  • When the key is pushed in while in the ACC position, the rotor and push plate are pushed in also. The upper part of the stopper plate therefore rides up the diagonal wall of the groove in the push plate, and the lower part of the push plate goes into the camshaft. The ignition key, push plate, and camshaft are therefore free to turn as on unit from the ACC position to the LOCK position. However, since the end of the lock release lever is still being hold down by the key, it prevents the lock stopper and lock bar from moving to the left.
  • When the ignition key is removed When the key is pulled out from the rotor, the lock release lever disengages (moves up) from the lock stopper, and the lock bar goes into the steering main shaft groove, locking the steering main shaft.

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  • The injection pump is driven by the camshaft in accordance with the engine. The fuel, which is highly compressed by the injection pump, is sent into the injection nozzle of each cylinder in order to be injected into the combustion chamber. Excess fuel is also returned to the fuel tank.
  • In following cases, bleed the air between the injection pump and injection nozzle (high pressure side).
  • When the engine does not operate properly after the engine is warmed up
  • When a part on the high pressure side of the fuel system are replaced
  • Abnormal wear and damage inside the cylinder and damage mainly occur for the following reasons:

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Insufficient lubrication

Improper maintenance of the engine oil or oil filter

Dust being sucked into the engine

Air-fuel mixture too rich



ExampleAmount of crankshaft offset

1NZ-FE and 2NZ-FE engines12 mm (0.472 in.)

1SZ-FE and 2SZ-FE engines8 mm (0.315 in.)

The numbers for the journal installation

position and installation orientation are

inscribed on the crankshaft bearing cap.

ExampleZZ engine series.

Some bearing caps are single unit with

ladder-frame construction, which consists

of the bottom of the cylinder block.

  • When measuring the ring end gap, insert the piston ring in the piston cylinder at the place with the least amount of wear.
  • The position for measuring the ring end gap differs according to the engine models.
  • Valve springs have the natural frequency. When the number of the valve opening and closing and the natural frequency match to vibrate together, the waviness vibration may occur irrelevant to camshaft operation. This condition is called surging and it can be a cause of abnormal engine noise as well as damage to the valve spring or interference between the valve and piston.
  • Asymmetrical type of uneven pitch springs is installed with the wider pitch toward the top.
  • Valve stickingoccurs when the valve stem in the valve bushing guide stops moving smoothly or stops moving completely. This occurs when the amount of clearance between the valve stem and the valve guide bushing is too small or when they are not sufficiently lubricated. If the valve stem oil seal is broken or hardens, engine oil will enter the combustion chamber and be burned. This can cause excessive oil consumption.
  • The optimal valve timing is predetermined for each engine models. If valve timing is not correct, engine idling will be unstable or there will be a drop in output. If the timing belt is broken or cut off, the rotational movement of the camshaft is stopped, and the piston could interfere with valves. Then pistons, valves and valve lifters etc., could be damaged. For that reason, in engines with timing belts, they are replaced every 100,00km (60,00miles) or 150,00km (90,00miles). In some engines, however, even if the timing belt is cut off, the top surface of the piston is constructed with a valve cut-out to prevent the piston from making contact with the valves. This type of engine requires that the timing belt be replaced when it breaks and is not set as a periodic maintenance item.
  • Timing chains are maintenance-freemeaning that they do not need periodic replacement
  • Valve Clearance
  • Since each engine part (cylinder head, cylinder block and valves, etc.) is subject to heat expansion, there must be clearance between the cam and valve lifter (shim) so that the valves can still smoothly operate even when affected by heat expansion. This clearance is called valve clearance.
  • Excessive valve clearance can be a cause of abnormal engine noise and valve mistiming.
  • Insufficient valve clearance can cause the piston to thrust up into the valve up.
  • There are two types of valve clearance, depending on the construction and materials of the engine. One type increases as the engine heats up while the other type decreases as the engine heats up.
  • When the relief valve sticks, the oil pressure will fail to rise or rise abnormally causing lubricated parts to seizure or oil leaks to occur. Also, when the sliding parts inside the pump wear out, or the gasket or O-ring is damaged, this causes the oil pressure to drop.
  • An engine equipped with a thermostat with bypass valve should not be run with the thermostat removed. The bypass circuit is wider in engines with a bypass valve. If the engine is run while the bypass valve (thermostat) is removed, more coolant will flow through the bypass circuit, making it easier for the engine to overheat.
  • Always be sure that the ignition switch is turned off when working near the engine cooling fan or radiator grille. The electrical cooling fan is temperature controlled, so if the ignition switch is turned on, there is the danger of the fan automatically starting to operate when the coolant temperature rises.
  • Engine Temperature-controlled Fluid Coupling
  • Disconnect connectors of all injectors so that fuel cannot be injected.
  • Remove the igniter or disconnect connectors of the igniter so that a spark is not generated.
  • The fully charged battery should be used to obtain an engine speed of over 25rpm.
  • If the compression pressure is low, pour a small amount
  • of engine oil in the spark plug hole. Measure the compression pressure again.
  • When the compression pressure risesA piston ring or cylinder bore may be worn or damaged.
  • When the compression pressure stays lowA valve may be sticking, a valve seat may be improper, or there may be leakage from the gasket.
  • The breaker points must be regularly adjusted or replaced. An external resistor is used for reducing the number of windings of the primary coil, improving the rise of the primary current, and minimizing the reduction in the secondary voltage at high speeds. Reducing the number of windings of the primary coil reduces resistance, increases the primary current, and increases the generation of heat. For this reason, an external resistor is provided to prevent the primary current from increasing excessively
  • In the past, ignition systems used a governor advancer and vacuum advancer to control timing advancing and retarding. However, most ignition systems today use the ESA system.
  • On some models, an IGF signal is determined through the primary voltage.
  • The fuel pressure regulator of 1NDTV E/G has a different appearance, but functions the same.
  • The fuel pressure regulator of 1NDTV E/G has a different appearance, but functions the same.

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  • If the required voltage can be provided despite a wide gap, the spark plug will be able to produce a strong spark and facilitate ignition. For this reason, there are many spark plugs on the market with a gap as wide as 1.1 mm. The platinum- and iridium-tipped spark plugs do not require gap adjustments because they are not susceptible to wear (they only need to be replaced).
  • The most appropriate spark plug heat range for a particular vehicle is determined by the model. Installing a spark plug of a different heat range will upset the selfcleaning and pre-ignition temperatures. To prevent these problems, always use the specified type of spark plugs for replacement. Using a cold spark plug when the engine is operating under low-speed and low-load conditions will reduce the electrode temperature and cause the engine to run poorly. Using a hot spark plug when the engine is operating under high-speed and heavy-load conditions will excessively increase the electrode temperature, causing the electrode to melt.
  • Some of these plugs do not have platinum welded onto their ground electrodes.
  • Platinum- and iridium-tipped spark plug replacement intervalsEvery 100,00to 240,000km The replacement intervals may vary by vehicle model, engine specifications, and area of use.
  • To prevent the electrodes from being damaged, do not clean platinum- or iridium-tipped spark plugs. Cleaning will damage the electrodes and will inhibit the full ability of the spark plugs. However, if the electrodes are sooty or excessively dirty, they may be cleaned for a short period of time (2seconds maximum) in a spark plug cleaner. The gap of these spark plugs does not require adjustment except when installing as new. The illustration on the left shows the type of caution label that is affixed in the engine compartment of a vehicle using platinum- or iridium-tipped spark plugs.
  • If a spark plug of an improper heat range is used, it may cause the spark plug to accumulate carbon on the electrode or to melt.

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  • Vehicles equipped with the catalytic converter need to use unleaded gasoline, because lead adheres to the surface of catalyst and the oxygen sensor (O2 sensor), and the appropriate effect cannot be attained if leaded gasoline is used.

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  • Caution is necessary for handling vehicles because the turbocharger becomes extremely hot due to the exhaust gases. Also, it is necessary to faithfully replace the engine oil at the determined replacement interval. Refer to the Precautions for Turbocharger for more information.
  • With some gasoline engine, the boost pressure is also controlled in accordance with the octane rating of the fuel used (premium or regular gasoline).
  • Relationship between Boost Pressure and EngineSpeed
  • The turbocharger temperature does not rise too high while driving as the turbocharger is cooled by the oil and coolant. When the engine is stopped immediately after high-speed driving, etc., circulation of the oil and coolant stop. This causes the turbocharger to remain uncooled, leading to damage such as sticking. Thus, it is necessary to idle and cool the turbocharger.
  • Valve clearance is adjusted using two adjusting screws, (
  • The intake shutter is also called throttle valve.

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  • As the maximum speed adjusting screw and full-load setting screw are adjusted to the proper position and sealed, normally they are not adjusted. However, if due to changes with the passing of time, adjustment becomes necessary, break the seal and perform an adjustment. After an adjustment, the maximum speed adjusting screw and full-load setting screw must be sealed.
  • If the vacuum hose connected to the sensor comes off, the fuel injection volume will reach the maximum, and the engine will not run properly. In addition, if the connector comes off, the engine ECU will switch to the fail-safe mode
  • Some models use a fuel control connector in place of a fuel control switch. This connector should be connected when premium gasoline is used, and is disconnected when regular gasoline is used. In other models, this is reversed. For information regarding the connector position or the regular/premium gasoline switching method, refer to the Owners Manual.
  • The fuel pressure can be inspected easily by the screw of the pulsation damper.
  • Some engine models do not have a pulsation damper.
  • Handling of the O-ring:
  • The O-ring must not be reused.
  • When installing the O-ring, first coat it with new gasoline.
  • When installing the injector to the delivery pipe, be careful not to damage the O-ring.
  • With the injector installed in the delivery pipe, turn the indicator by hand. If it does not rotate smoothly, the Oring is damaged.
  • There are some vehicles equipped with a DLC1 as shown at left. When +B terminal and FP terminal of the DLC1 are shorted using an SST with the ignition switch turned ON, the current will flow to the fuel pump without passing through the circuit opening relay to operate the fuel pump. In this way, the inspection of the fuel pressure or pump operation can be performed by forcing the fuel pump to operate.
  • Install the injection pump by aligning the matching mark on the injection pump with the reference position mark on the engine. Because the ECU recognizes the injection timing and makes appropriate corrections, it is not necessary to adjust the injection timing after assembly, as with the mechanical diesel pump.

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  • When inspecting the engine ECU terminal voltage, the NE signal, KNK signal and etc. are output in an AC waveform. Therefore, highly accurate measurements can be taken using an oscilloscope
  • The voltage (V) required to raise the temperature of the hot-wire (Rh) by the amount of T from the intake air temperature remains constant at all times even if the intake air temperature changes. In addition, the cooling capacity of the air is always proportional to the intake air mass. Consequently, if the intake air mass remains the same, the output of the air flow meter will not change even if there is a change in intake air temperature
  • Do not remove the sensor. Extremely fine position adjustment is required when installing the sensor. Therefore, replace the accelerator pedal assembly when the sensor malfunctions.
  • When a G signal from the sensor is not received by the engine ECU, there are models where the engine keeps running, and a model where the engine stops.
  • When the NE signal from the sensor is not received by the engine ECU, the engine ECU determines that the engine has stopped, causing the engine to stop.
  • The glow indicator light operates independently from the glow plug. Thus, it does not indicate whether plug has actually heated up or not. The light lighting time is approx. 0- 1seconds. The light lighting time varies according to the coolant temperature and according to the engine models.
  • As the vane type air flow meter has an idle mixture adjusting screw in its body, a variable resistor is not required even if there is no oxygen sensor.
  • When there is a malfunction with the water temperature sensor, it can be considered as the worse startability.
  • When there is a malfunction with the water temperature sensor, it can be considered as poor drivability.
  • For hot-wire type air flow meters, the air flow meter itself outputs a corrective signal for the intake air temperature. Therefore, intake air temperature correction is not required.
  • Depending on the engine model, there are some types that determine the engine is being started when the engine ECU receives a starter signal (STA).
  • In some engine models the basic ignition advance angle is changed depending on whether or not the air conditioner is ON or OFF. In addition, of these models, some have an advance angle of 0 during standard idling speed.
  • For some engine models, the IDL signal or NE signal is used as a related signal for this correction.
  • Some engine models also use the following signals for correction.
  • Intake air mass signal (VG or PIM)
  • Engine speed signal (NE)
  • Throttle position signal (IDL)
  • When the IDL signal is off, even if there is a short between the TE1 (TC) and E1 (CG) terminals, the ignition timing cannot be set.
  • For recent models, the ignition timing cannot be adjusted because sensors for the G and NE signals are fixed to the engine.
  • When the engine ECU detects a malfunction, it turns ON the malfunction indicator lamp in the combination meter while cutting off the power to the motor, but because the throttle valve is kept open to approx. 7

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  • low speed operation lowers the voltage applied to the motor using a resistor placed in series in the circuit to reduce the cooling fan speed, or two motors are connected in series to reduce the fan speed.

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  • The glass part and electrodes of discharge headlight bulbs generate dangerously high voltage (approx. 20,000 V). Do not touch them.
  • Turn the lights on only after the bulbs are completely installed. Do not use any power source other than the vehicle’s.
  • When replacing the bulbs, be sure to follow the procedure in the Repair Manual.

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  • If the cam switch in the wiper motor becomes damaged and the wiring connecting the wiper switch and cam switch opens, the following symptoms will occur:
  • When cam switch is damaged
  • If contact point P3 is damaged while the wiper motor is operating, contact point P1 will have no continuity with contact point P3 when the wiper switch is off. As a result, the electric brake will not apply to the wiper motor and the wiper motor cannot stop at the specified position, causing the wiper motor to continue turning.
  • When the wiring between wiper switch terminal 4 and the wiper motor opens
  • Normally, when the wiper switch is turned to the OFF position, the wiper blade operates until the stopping position, but if the wiring between wiper switch terminal 4 and the wiper motor opens, the wiper blade does not reach the stopping position but stops instantly at the position when the switch is turned off.

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  • There are two types of side airbag sensors (side and curtain shield airbag sensor) and curtain shield airbag sensor: One with a built-in safing sensor and one without.
  • The method by which the safety device is activated or deactivated varies according to the model. Make sure to activate and deactivate the safety device in accordance with the instructions contained in the Repair Manual or on the caution label affixed to the pretensioner.
  • When the airbag and/or seat belt pretensioners is deployed, each of the parts listed below is very hot, so leave it alone for at least 30 minutes after deployment.
  • Steering wheel pad (with airbag)
  • Front passenger airbag assembly
  • Front seat outer belt (with seat belt pretensioners)
  • Side airbag assembly
  • Curtain shield airbag assembly
  • Use gloves and safety glasses when handling each of the parts listed below. In addition, do not apply water to then.
  • Steering wheel pad with deployed airbag
  • Deployed front passenger airbag assembly
  • Front seat outer belt with deployed seat belt pretensioners
  • Deployed side airbag assembly
  • Deployed curtain shield airbag assembly
  • Always wash your hands with water after completing the operation.

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  • The compressor oil used in the R-134a system is not interchangeable with the one used in the R-12 system. If the wrong type of oil is used, it may lead to compressor seizure.
  • In the sub-cool cycle, the point where bubbles disappear is before the cooling capability stabilizing range, which requires 100 g more refrigerant to reach the appropriate filling amount. If filling of refrigerant stops at the point where bubbles disappear, cooling capability is not enough. Further, overcharging decreases fuel economy and cooling capability, so be sure to fill the appropriate amount of refrigerant.
  • For the vehicle with EPR, since the low-pressure side is controlled with EPR, abnormal values may not be indicated directly on the gauge pressure.

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