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Home >> Subaru >> 2006 >> Baja Turbo, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 16 (Automatic Transmission Diagnostics (4AT) (H4SO)) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC 93 Rear Vehicle Speed Sensor

DTC 93 Rear Vehicle Speed Sensor

WARNING: This page is about a different variant/trim than selected.

DIAGNOSIS: 

The input signal circuit of TCM is open or shorted.

TROUBLE SYMPTOM: 

No lock-up or excessive tight corner "braking".

WIRING DIAGRAM: 

Fig 1: Rear Vehicle Speed Sensor - Wiring Diagram
G04990743Courtesy of SUBARU OF AMERICA, INC.
DIAGNOSTIC PROCEDURE CHART

Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from TCM and transmission.
  3. Measure the resistance of harness between TCM and transmission connector.

    Connector & terminal 

    (B55) No. 3 - (B11) No. 19: 

 Is the resistance less than 1 Ω? Go to step 2.  Repair the open circuit in harness between TCM and transmission connector.
2 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
Measure the resistance of harness between TCM and transmission connector.
Connector & terminal 
(B55) No. 21 - (B11) No. 20: 		 Is the resistance less than 1 Ω? Go to step 3.  Repair the open circuit in harness between TCM and transmission, and poor contact in coupling connector.
3 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
Measure the resistance of harness between TCM and chassis ground.
Connector & terminal 
(B55) No. 3 - Chassis ground: 		 Is the resistance more than 1 MΩ? Go to step 4.  Repair the short circuit in harness between TCM and transmission connector.
4 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
Measure the resistance of harness between TCM and chassis ground.
Connector & terminal 
(B55) No. 21 - Chassis ground: 		 Is the resistance more than 1 MΩ? Go to step 5.  Repair the short circuit in harness between TCM and transmission connector.
5 CHECK REAR VEHICLE SPEED SENSOR. 
Measure the resistance between transmission connector receptacle's terminals.
Connector & terminal 
(T4) No. 19 - No. 20: 		 Is the resistance 450 - 650 Ω? Go to step 6.  Replace the rear vehicle speed sensor. < Ref. to REAR VEHICLE SPEED SENSOR . >
6 PREPARE OSCILLOSCOPE.  Do you have an oscilloscope? Go to step 10.  Go to step 7. 
7 PREPARE SUBARU SELECT MONITOR.  Do you have a Subaru Select Monitor? Go to step 9.  Go to step 8. 
8 CHECK INPUT SIGNAL FOR TCM. 
  1. Connect the connectors to TCM and transmission.
  2. Lift-up or raise the vehicle and place safety stands.
    NOTE: Raise all wheels off floor.
  3. Start the engine and set vehicle in 20 km/h (12 MPH) condition.
    NOTE: The speed difference between front and rear wheels may light the ABS warning light, but this indicates no malfunction. When AT control diagnosis is finished, perform the ABS memory clearance procedure of on-board diagnostics system. < Ref. to CLEAR MEMORY MODE . >
  4. Measure the voltage between TCM connector terminals.

    Connector & terminal 

    (B55) No. 3 (+) - (B55) No. 21 (-): 

 Is the voltage more than AC 1 V? Even if the AT OIL TEMP warning light blinks, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector or harness may be the cause. Repair the harness or connector in TCM and transmission. Go to step 11. 
9 CHECK INPUT SIGNAL FOR TCM USING SUBARU SELECT MONITOR. 
  1. Connect the connectors to TCM and transmission.
  2. Connect the Subaru Select Monitor to data link connector.
  3. Lift-up or raise the vehicle and place safety stands.
    NOTE: Raise all wheels off floor.
  4. Turn the ignition switch to ON and turn Subaru Select Monitor switch to ON.
  5. Start the engine.
  6. Read the data of vehicle speed using Subaru Select Monitor.
    • Compare the speedometer with Subaru Select Monitor indications.
    • Vehicle speed is indicated in "km/h" or "MPH".
  7. Slowly increase the vehicle speed to 60 km/ h or 37 MPH.
NOTE: The speed difference between front and rear wheels may light the ABS warning light, but this indicates no malfunction. When AT control diagnosis is finished, perform the ABS memory clearance procedure of on-board diagnostics system. < Ref. to CLEAR MEMORY MODE . >
 Does the speedometer indication increase as the Subaru Select Monitor data increases? Even if the AT OIL TEMP warning light blinks, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector or harness may be the cause. Repair the harness or connector in TCM and transmission. Go to step 11. 
10 CHECK INPUT SIGNAL FOR TCM USING OSCILLOSCOPE. 
  1. Connect the connectors to TCM and transmission.
  2. Lift-up or raise the vehicle and place safety stands.
    NOTE: Raise all wheels off floor.
  3. Set the oscilloscope to TCM connector terminals.

    Connector & terminal 

    Positive probe; (B55) No. 3: 

    Ground lead; (B55) No. 21: 

  4. Start the engine and set vehicle in 20 km/h (12 MPH) condition.
    NOTE: The speed difference between front and rear wheels may light the ABS warning light, but this indicates no malfunction. When AT control diagnosis is finished, perform the ABS memory clearance procedure of on-board diagnostics system. < Ref. to CLEAR MEMORY MODE . >
  5. Measure the signal voltage indicated on oscilloscope.
 Is the signal voltage more than AC 1V? Even if the AT OIL TEMP warning light blinks, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector or harness may be the cause. Repair the harness or connector in TCM and transmission. Go to step 11. 
11 CHECK POOR CONTACT.  Is there poor contact in rear vehicle speed sensor circuit? Repair the poor contact. Replace the TCM. < Ref. to TRANSMISSION CONTROL MODULE (TCM) . >

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