a) Remove the center panel.
b) Turn on the ignition.
c) Measure the voltage at each terminal of the automatic transmission and engine control unit connector (see table "Voltage at the terminals of the automatic transmission control unit connector").
Signal form between terminals "SPD" and "E1" at a speed of at least 20 km/h. Division value (cells) 5 V and 20 ms.
Signal shape between pins "SLD+" and "E1" and "SLD-" and PEG\ Division value (cells) 5 V and 1 ms. Ignition key in the ON position.
2. Check the engine start inhibit switch.
Check for conductivity between the connector terminals indicated in the table.
(): for A540H.
If there is no continuity between the specified terminals, replace the start inhibit switch.
3. Check the solenoid valves.
a) Disconnect the solenoid valve connector.
b) Measure the resistance between the terminals "S1", "S2", "SL" and "land".
- Nominal resistance - 11 - 15 Ohm
A140N
A540N
c) Apply battery voltage to each contact. A click indicates that the electromagnetic valves are working.
The location of the electrical components of the gearbox control system.
1 - electromagnetic valve of torque converter lock-up,
2 - engine coolant temperature sensor,
3 - throttle position sensor,
4 - diagnostic connector,
5 - engine start prohibition switch,
6 - electromagnetic valve No.1,
7 - electromagnetic valve No.2,
8 - rear output shaft speed sensor,
9 - electromagnetic valve for locking the interaxle differential,
10 - automatic transmission fluid overheating sensor,
11 - front output shaft speed sensor,
12 - automatic transmission operating mode selection switch,
13 - vehicle speed sensor (instrument cluster),
14 - electronic control unit of automatic transmission,
15 - Overdrive switch (O/D),
16 - brake light switch.
4. Check the conductivity between terminals "2" and "4" of the overdrive switch connector. When the overdrive mode is on, there should be no conductivity; when it is off, there should be conductivity. Otherwise, replace the switch.
5. Check the conductivity between the terminals of the automatic transmission mode selection switch connector, as indicated in the table.
Except A140E (since May 1996.)
Note: The switch illumination lamp is connected to the "R" and "G" terminals.
Except A140E (may 1996.)
A140E (since May 1996.)
Note: the switch illumination lamp is connected to terminals "2" and "4".
A140E (since May 1996.)
6. Check the engine coolant temperature sensor.
Measure the resistance between the sensor connector contacts. Replace the sensor if the resistance is not within the range shown in the figure.
Table. Voltage at the terminals of the automatic transmission control unit connector.
A140E.
Models without traction control (TRC)
Models with traction control (TRC)
(): for models without traction control system (TRC).
7. (A540N)
Check the center differential lock solenoid valve
a) Connect the positive terminal of the battery through a 24W lamp to terminal "1" of the valve connector and the negative terminal of the battery to terminal "2", the valve should move.
b) Check the resistance between terminals "1" and "2" of the solenoid valve connector
- Nominal resistance - 5.1 - 5.5 Ohm
8. (A540N)
Check the RPM sensors (front and rear output shaft).
a) Disconnect the connector of the electronic control unit of the automatic transmission and check between the connector terminals 6 -19 (front Output Shaft Speed Sensor) and 21 - 22 (rear output shaft speed sensor) resistance.
- Nominal resistance - 560 - 680 Ohm
b) Disconnect the sensor connectors and remove the gearbox output shaft speed sensors.
c) Using an ohmmeter, check the resistance between the connector terminals
- Nominal resistance - 560 - 680 Ohm
9. (A540H)
Check the conductivity between the terminal and the body of the automatic transmission fluid overheating sensor connector when the fluid temperature changes as shown in the figure.
If the conductivity does not match the specified value, replace the sensor.
Table. Voltage at the terminals of the automatic transmission control unit connector.
A140E (since May 1996.)
10. Check the brake light switch.
Check the continuity between terminals "1" and "2" of the brake light switch connector.
There should be conductivity when the pedal is pressed, there should be no conductivity when the pedal is released. Otherwise, replace the brake light switch.
Table. Voltage at the terminals of the automatic transmission control unit connector (continuation). A540H (3S-FE).
