- a) Reduced engine recoil efficiency;
- b) Violation of regulations;
- c) Hydraulics malfunction;
- d) Mechanical damage;
- e) Failures of the onboard processor / its signal circuit.
Failure diagnosis should always start with the simplest checks: check the level and condition of the ATF (see chapter Settings and ongoing maintenance), check the adjustment of the gearshift and throttle actuators. Next, test drive the vehicle to determine the effectiveness of the corrections made. If the problem cannot be fixed, you should drive the car to a service station for more detailed diagnostics using special equipment. A description of some of the symptoms of AT failures is given in the Section on the diagnosis of failures of vehicle components and systems at the beginning of this Guide.
Primary Checks
1. During a short drive, warm up the transmission to normal operating temperature.
2. Check the ATF level (see chapter Settings and ongoing maintenance):
- a) If the liquid is clearly not enough, make the appropriate adjustment by adding the required amount of fresh ATF. Verify that the dipstick adjustment is correct, then check the transmission for signs of external leaks (see below);
- b) If the level is excessively high, drain excess ATF, then check it for signs of coolant presence, indicating a leak in the internal bulkheads of the radiator separating its heat exchanger from the side tanks with ATF (see chapter Cooling, heating systems);
- c) If the ATF is foamy, empty the transmission and refill it with fresh fluid - check the drained ATF for signs of coolant presence.
3. Check engine idle speed setting (see chapter Power and exhaust systems). If necessary, drive the car to a workshop to make the appropriate adjustments.
Note. If the engine is out of order, you should not proceed with the initial checks of the transmission until the appropriate corrections have been made.
4. Check the freedom of movement of the shift control cable (see Section Checking, adjusting and replacing the shift cable), make sure that the adjustment is correct and the traction moves smoothly.
Diagnosis of ATF leaks
General information
Most leaks are easily identified by visual inspection. Repair usually consists of replacing the corresponding defective oil seal or gasket. If the external inspection fails to identify the source of the leak, proceed as described below.
First of all, it is necessary to exclude the possibility of error in determining the nature of the leak. ATF should not be confused with engine oil or brake fluid (transmission fluid is usually dark red in color).
Run a short test to find the source of the leak (several kilometers) ride, then park the car over a blank sheet of cardboard. After a couple of minutes, the source of the leak can be identified by traces of liquid dripping onto the cardboard.
Carefully inspect the suspected area and the surrounding surface, paying special attention to the joints of the mating gasket surfaces. In order to expand the viewing angle, use a pocket mirror.
If you still cannot find the source of the leak, carefully wipe the surface of the suspected area with a rag soaked in solvent, then dry it.
Make another short drive, this time changing your speed frequently, then re-examine the cleared suspect area.
After identifying the source of the leak, it is necessary to determine and eliminate the cause of its development, and only then proceed to perform the necessary restoration work. Replacing a damaged gasket will not lead to the desired result if the defect in the mating surface that led to the failure of the seal is left unrepaired. So, the deformed flange must be straightened.
The following subsections list the most common causes of ATF leaks and the conditions that must be met to prevent recurrence.
Note. Some of the listed requirements cannot be met without the use of special equipment. In this case, the car should be driven to a service station.
Leakage through gasket surfaces
Periodically inspect the transmission oil pan. Check that the fixing bolts are in place and securely tightened, make sure that there are no signs of mechanical damage on the cover (deformation of the sump can lead to failure of the valve assembly located inside the transmission).
Potential causes of sump leaks include overtightening of mounting bolts, damage to the transmission case sealing surface, gasket failure, and cracked or porous crankcase walls. If the gasket of the pan or transmission case is formed by a sealant pad, the possibility of an incorrect choice of the type of the latter cannot be ruled out. Pan gasket leaks can also be caused by overfilling the crankcase with transmission fluid or by increasing ATF pressure.
Leaks through glands and cuffs
The most typical causes of failure of transmission oil seals include an excessively high level of ATF, a violation of the patency of the ventilation pipe, mechanical damage to the walls of the seat, damage to the oil seal itself, or improper installation of the latter. It is also possible that the trunnion of the shaft threaded into the stuffing box is damaged, or the latter has excessive play as a result of bearing wear.
Check the condition and correct fit of the sealing collar of the dipstick guide tube. Periodically inspect the surface around the speedometer/speedometer drive gear for signs of leaks (VSS). If necessary, replace the sealing ring.
Leaks through defects in the walls of the transmission case
The reason for the development of ATF leaks may be the formation of cracks or pores in the body of the transmission case. Consult a car service specialist.
Check the tightness of the union connections of the ATF cooler hoses.
Leaks through the breather and filler neck
Breather or filler leaks can be caused by an overfilled transmission, coolant in the ATF, a blocked breather/vent or return drains.
Diagnostic trouble codes AT
The on-board processor responsible for the functioning of the AT constantly monitors violations in the system (including contours of information sensors and actuators). If a malfunction is detected, the corresponding diagnostic code is stored in the memory of the control unit. At the service station, the fault codes stored in the memory of the processor can be retrieved using a device known as "CONSULT", or readers of scanner type. The vehicle owner can read the codes himself using the signals displayed by the upshift off indicator lamp "OD OFF" on the car's dashboard.
Models 1993 and 1994 issue
1. Start the engine and warm it up to normal operating temperature.
2. Turn the ignition key to the OFF position.
3. Move the AT mode selector to the AUTO position.
4. Move the overdrive mode switch to the ON position.
5. Move the selector lever to position "R".
6. Without starting the engine, turn on the ignition.
7. The OD OFF indicator lamp should turn on for approximately two seconds:
- a) Failure to turn on the lamp indicates a malfunction of the AT operation control processor (first make sure that the lamp itself has not failed). The compilers of this Guide do not recommend measuring the resistance and voltage at the processor terminals, since accidental voltage surges / passing excessively high current through the control unit can damage the latter. Take the vehicle to a service station for inspection.
- b) If the OD OFF indicator lamp works properly, proceed to the next step of the test.
8. Turn off the ignition.
9. Move the selector lever to position "D".
10. Disengage the overdrive by turning the mode switch to the OFF position.
11. Without starting the engine, turn on the ignition.
12. After at least two seconds after switching on the ignition, move the selector lever to the position "2".
13. Turn the switch to the ON position to shift up.
14. Move the selector lever to position "1".
15. Disable overdrive mode (OFF).
16. Squeeze out a gas pedal against the stop, then release it.
17. Now the processor should switch to the mode of issuing information. Reading of the codes of malfunctions brought in memory of the block can be made on flashes of a control lamp OD OFF.
Models from 1995 to 1997 issue
1. Start the engine and warm it up to normal operating temperature.
2. Turn off the ignition and wait at least five seconds before proceeding with the procedure.
3. Turn the ignition key to the ACC position
4. Move the overdrive mode switch to the ON position.
5. Move the selector lever to position "R".
6. Without starting the engine, turn on the ignition.
7. The OD OFF indicator lamp should turn on for approximately two seconds:
- a) Failure to turn on the lamp indicates a malfunction of the AT operation control processor (first make sure that the lamp itself has not failed). The compilers of this Guide do not recommend measuring the resistance and voltage at the processor terminals, since accidental voltage surges / passing excessively high current through the control unit can damage the latter. Take the vehicle to a service station for inspection.
- b) If the OD OFF indicator lamp works properly, proceed to the next step of the test.
8. Turn off the ignition.
9. Switch on the ignition again without starting the engine.
10. Move the selector lever to position "D".
11. Disengage the overdrive by turning the mode switch to the OFF position.
12. Without starting the engine, turn on the ignition.
13. After at least two seconds after switching on the ignition, move the selector lever to the position "2".
14. Turn the switch to the ON position to shift up.
15. Move the selector lever to position "1".
16. Disable overdrive mode (OFF).
17. Squeeze out a gas pedal against the stop, then release it.
18. Now the processor should switch to the mode of issuing information. Reading of the codes of malfunctions brought in memory of the block can be made on flashes of a control lamp OD OFF.
Models 1998 and 1999 issue
1. Start the engine and warm it up to normal operating temperature.
2. Turn off the ignition and wait at least five seconds before proceeding with the procedure.
3. Move the AT mode selector to the position "R".
4. Without starting the engine, turn on the ignition.
5. The OD OFF indicator lamp should turn on for approximately two seconds:
- a) Failure to turn on the lamp indicates a malfunction of the AT operation control processor (first make sure that the lamp itself has not failed). The compilers of this Guide do not recommend measuring the resistance and voltage at the processor terminals, since accidental voltage surges / passing excessively high current through the control unit can damage the latter. Take the vehicle to a service station for inspection.
- b) If the OD OFF indicator lamp works properly, proceed to the next step of the test.
6. Turn off the ignition.
7. Turn the ignition key to the ACC position.
8. Move the selector lever to position "D".
9. Without starting the engine, turn on the ignition.
10. Disable overdrive mode (push the switch button to the OFF position), then turn the ignition off and on again. Release the overdrive switch (the lamp should go out).
11. After at least two seconds after switching on the ignition, move the selector lever to the position "2".
12. Press the overdrive switch button and, while holding it pressed, move the selector lever to the position "1".
13. Turn off the overdrive (the lamp should go out).
14. Squeeze out a gas pedal against the stop, then release it.
15. Now the processor should switch to the mode of issuing information. Reading of the codes of malfunctions brought in memory of the block can be made on flashes of a control lamp OD OFF.
All models
1. If all monitored circuits are functioning properly, the control lamp will give one long flash, then ten short ones at regular intervals between them.
2. The beginning of the display of each of the codes is marked by one long flash, followed by ten consecutive flashes that determine the code number itself:
- a) If the first flash of ten significant is long, then there is a malfunction in the speed sensor circuit;
- b) A long second flash indicates a failure in the VSS circuit;
- c) The third long flash corresponds to a failure in the TPS circuit;
- d) The fourth is in the gear shift solenoid valve circuit A 4
- e) Fifth - in the circuit of the solenoid valve for shifting B;
- f) The sixth is in the overrunning clutch solenoid valve-switch circuit;
- g) The seventh - in the circuit of the electromagnetic valve-switch of the clutch of the rotation converter;
- h) Eighth - in the ATF temperature sensor circuit;
- i) The ninth is in the engine speed signal circuit;
- j) Tenth - in the circuit of the solenoid valve pressure in the path;
- k) Alternating long flashes with long eclipses of the pilot lamp indicates a low battery level;
- l) On models up to 1998, no. failure to turn on the OD OFF warning lamp indicates a malfunction of the start/reverse light switch, overdrive switch, or TPS;
- m) On 1999 models, no. failure to turn on the lamp is usually associated with a failure of the start enable/reverse lights switch sensor, or TPS.
3. The elimination of faults identified during the inspection requires high qualifications from the performer and should be entrusted to car service specialists. The only exception is the repair / replacement of VSS and TPS (see chapter Engine management systems).
Clearing the processor memory from codes
1. Cleaning the processor memory is one of the repair procedures performed by the service station specialists. If the reading of the codes and the necessary corrections were made by the owner of the car on their own, proceed in the following order:
2. Turn off the ignition (if it is enabled), wait at least five seconds, and then turn it on again.
3. Perform trouble code reading procedures (see above).
4. By turning the selector on the control module (RSM), switch the system from Mode II to Mode I (see chapter Engine management systems).