Transmission Control Systems

DIAGNOSIS
Input signal circuit of TCM is open or shorted.

TROUBLE SYMPTOM
No locking-up or excessive tight corner "braking"

CHECK HARNESS CONNECTOR BETWEEN TCM AND VEHICLE SPEED SENSOR 1
1. Turn ignition switch to OFF.
2. Disconnect connectors from TCM and transmission.





3. Measure resistance of harness connector between TCM and transmission connector.
Connector & terminal / Specified resistance:
(B54) & No. 12 and (B11) & No. 16 / 1 ohms, or less
(B54) & No. 7 and (B11) & No. 9 / 1 ohms, or less





4. Measure resistance of harness connector between TCM and body to make sure that circuit does not short.
Connector & terminal / Specified resistance:
(B54) & No. 7 and Body / 1 M ohms, or more
(B54) & No. 12 and Body / 1 M ohms, or more





CHECK VEHICLE SPEED SENSOR 1
1. Measure resistance between transmission connector receptacle's terminals.
Connector & terminal / Specified resistance:
(T4) & No. 16 and No. 9 / 450 - 720 ohms





2. Measure resistance of harness connector between transmission connector and transmission case to make sure that circuit does not short.
Connector & terminal / Specified resistance:
(T4) & No. 16 and Transmission / 1 M ohms, or more
(T4) & No. 9 and Transmission / 1 M ohms, or more

CHECK INPUT SIGNAL FOR TCM
1. Connect connectors to TCM and transmission.
2. Lift-up or raise the vehicle and place safety stands.

CAUTION: On AWD models, raise all wheels off floor.

3. Push the TCS OFF switch to ON. (With TCS models)
4. Start the engine and set vehicle in 20 km/h (12 MPH) condition.





5. Measure voltage between TCM connector terminals.
Connector & terminal / Specified voltage:
(B54) & No. 12 and No. 7 / AC 1 Volt, or more

NOTE: The speed difference between front and rear wheels may light either the ABS or the ABS/TCS warning light, but this indicates no malfunctions. When AT control diagnosis is finished, perform the ABS or the ABS/TCS memory clearance procedure of self-diagnosis system. Refer to Brakes and Traction Control.





Using Subaru select monitor, or equivalent:
1. Connect connectors to TCM and transmission.
2. Turn ignition switch to OFF.
3. Connect the Subaru select monitor, or equivalent to data link connector.
4. Lift-up or raise the vehicle and place safety stands.

CAUTION: On AWD models, raise all wheels off floor.

5. Turn ignition switch to ON and Subaru select monitor switch to ON.
6. Push the TCS OFF switch to ON. (With TCS models)
7. Start the engine and operate at constant speed.
8. Read data on Subaru select monitor, or equivalent.
9. Designate mode using function key.
Function mode: F02 or F03

Specified Data
- F02: Compare speedometer with monitor indications.
- F03: Compare speedometer with monitor indications.





- F02: Vehicle speed is indicated in "m/h".





- F03: Vehicle speed is indicated in "km/h".

NOTE: The speed difference between front and rear wheels may light either the ABS or the ABS/TCS warning light, but this indicates no malfunctions. When AT control diagnosis is finished, perform the ABS or the ABS/TCS memory clearance procedure of self-diagnosis system. Refer to Brakes and Traction Control.





Using Oscilloscope:
1. Connect connectors to TCM and transmission.
2. Lift-up the vehicle and place safety stands.

WARNING: On AWD models, make sure that all wheels are raised off floor.

3. Set oscilloscope to TCM connector terminals.
Connector & terminals:
Positive probe; (B54) & No. 12
Earth lead; (B54) & No. 7
4. Push the TCS OFF switch to ON. (With TCS models)
5. Start the engine, and set vehicle in 20 km/h (12 MPH) condition.





6. Measure signal voltage indicated on oscilloscope.
Specified voltage: AC 1 Volt, or more

NOTE: The speed difference between front and rear wheels may light either the ABS or the ABS/TCS warning light, but this indicates no malfunctions. When AT control diagnosis is finished, perform the ABS or the ABS/TCS memory clearance procedure of self-diagnosis system. Refer to Brakes and Traction Control.