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Home >> Subaru >> 2006 >> Legacy GT spec.B >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 16 (Automatic Transmission (Diagnostics) 4AT) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P1706 At Vehicle Speed Sensor Circuit Malfunction (Rear Wheel)

DTC P1706 At Vehicle Speed Sensor Circuit Malfunction (Rear Wheel)

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

DTC DETECTING CONDITION: 

Input signal circuit of TCM is open or shorted.

TROUBLE SYMPTOM: 

No lock up or tight corner braking phenomenon is occurred.

WIRING DIAGRAM: 

Fig 1: Vehicle Speed Sensor - Wiring Diagram
G05019788
RESISTANCE CHART

Step Check Yes No
1 CHECK IGNITION POWER SUPPLY CIRCUIT. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from rear vehicle speed sensor.

    Turn the ignition switch to ON.

  3. Measure the ignition power supply voltage between rear vehicle speed sensor connector and transmission ground.

    Connector & terminal 

    (AT13) No. 3 (+) - Transmission ground (-): 

Is the voltage more than 10 V? Go to step 2.  Check harness between rear vehicle speed sensor and battery for open circuit, short or poor contact. Repair the harness if required.
2 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
  1. Turn the ignition switch to OFF.
  2. Measure the resistance of harness between TCM connector and rear vehicle speed sensor connector.

    Connector & terminal 

    (B54) No. 23 - (AT13) No. 1: 

Is the resistance less than 1 Ω? Go to step 3.  Repair the open circuit or poor contact of the connector in harness between TCM and rear vehicle speed sensor connector.
3 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
Measure the resistance of harness between TCM connector and rear vehicle speed sensor connector.
Connector & terminal 
(B54) No. 24 - (AT13) No. 2: 
Is the resistance less than 1 Ω? Go to step 4.  Repair the open circuit or poor contact of the connector in harness between TCM and rear vehicle speed sensor connector.
4 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
Measure the resistance of the harness between TCM connector and chassis ground.
Connector & terminal 
(B54) No. 23 - Chassis ground: 
Is the resistance more than 1 MΩ? Go to step 5.  Repair the short circuit of harness between TCM and rear vehicle speed sensor connector.
5 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 
Measure the resistance of the harness between TCM connector and chassis ground.
Connector & terminal 
(B54) No. 24 - Chassis ground: 
Is the resistance more than 1 MΩ? Go to step 6.  Repair the short circuit of harness between TCM and rear vehicle speed sensor connector.
6 PREPARE OSCILLOSCOPE.  Do you have an oscilloscope? Go to step 8.  Go to step 7. 
7 CHECK INPUT SIGNAL FOR TCM. 
  1. Connect the connectors to TCM and transmission.
  2. Lift up the vehicle and support with rigid racks.
    NOTE: Raise all wheels off the 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 does not indicate a 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 AC voltage between TCM connector terminals.

    Connector & terminal 

    (B54) No. 24 (+) - No. 23 (-): 

Is the voltage approx. 2 V or more? Go to step 9.  Replace the rear vehicle speed sensor.
8 CHECK INPUT SIGNAL FOR TCM USING OSCILLOSCOPE. 
  1. Connect the connectors to TCM and transmission.
  2. Lift up the vehicle and support with rigid racks.
    NOTE: Raise all wheels off the floor.
  3. Set the oscilloscope to TCM connector terminals.

    Connector & terminal 

    Positive probe; (B54) No. 24: 

    Ground lead; (B54) No. 23: 

  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 does not indicate a 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 pulse voltage approx. 5 V? Go to step 9.  Replace the rear vehicle speed sensor.
9 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) . >