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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 without Diagnostic Trouble Code (DTC) >> Check Fwd Switch

Check Fwd Switch

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

DIAGNOSIS: 

WIRING DIAGRAM: 

Fig 1: FWD Switch - Wiring Diagram
G05019794
RESISTANCE CHART

Step Check Yes No
1 CHECK SPARE FUSE.  Is the spare fuse OK? Go to step 2.  Replace the fuse.
2 CHECK FWD SWITCH. 
Connect the Subaru Select Monitor to the data link connector.
When the fuse is inserted to FWD switch, does the LED illuminate? Go to step 3.  Go to step 4. 
3 CHECK COMBINATION METER.  Does the AWD warning light illuminate? Go to INSPECTION FOR SPORT SHIFT SWITCH. < Ref. to CHECK SPORT SHIFT SWITCH , Diagnostic Procedure without Diagnostic Trouble Code (DTC). > Go to step 9. 
4 CHECK HARNESS CONNECTOR BETWEEN TCM AND FWD SWITCH. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from TCM.
  3. Measure the resistance of harness between TCM and FWD switch connector.

    Connector & terminal 

    (B55) No. 17 - (F27) No. 18: 

Is the resistance less than 1 Ω? Go to step 5.  Repair the open circuit of harness between TCM and FWD switch connectors.
5 CHECK HARNESS CONNECTOR BETWEEN FWD SWITCH AND CHASSIS GROUND. 
Measure the resistance of harness between FWD switch and chassis ground.
Connector & terminal 
(F27) No. 19 - Chassis ground: 
Is the resistance less than 1 Ω? Go to step 6.  Repair the open circuit of harness between FWD switch connector and chassis ground.
6 CHECK HARNESS CONNECTOR BETWEEN TCM AND FWD SWITCH. 
Measure the resistance of harness connector between TCM and body to make sure that circuit does not short.
Connector & terminal 
(B55) No. 17 - Chassis ground: 
Is the resistance more than 1 MΩ? Go to step 7.  Repair the short circuit of harness between TCM and FWD switch connectors.
7 CHECK INPUT SIGNAL FOR TCM. 
  1. Turn the ignition switch to OFF.
  2. Connect the connector to TCM.
  3. Turn the ignition switch to ON.
  4. Measure the signal voltage for TCM while installing the fuse to FWD switch connector.

    Connector & terminal 

    (B55) No. 17 (+) - Chassis ground (-): 

Is the voltage less than 1 V? Go to step 8.  Go to step 10. 
8 CHECK INPUT SIGNAL FOR TCM. 
Measure the signal voltage for TCM with the fuse removed from FWD switch connector.
Connector & terminal 
(B55) No. 17 (+) - Chassis ground (-): 
Is the voltage more than 10.5 V? Go to step 9.  Replace the TCM. < Ref. to TRANSMISSION CONTROL MODULE (TCM) . >
9 CHECK THE BODY INTEGRATED UNIT. 
Check DTC of body integrated unit.
Is DTC of CAN communication displayed? Perform the diagnosis according to DTC. Go to step 10. 
10 CHECK COMBINATION METER. 
Check the AWD warning light. < Ref. to INSPECTION , Combination Meter System. >
Is the AWD warning light OK? Go to step 11.  Replace the combination meter assembly. < Ref. to COMBINATION METER . >
11 CHECK POOR CONTACT.  Is there poor contact in FWD switch circuit? Repair the poor contact. Replace the TCM. < Ref. to TRANSMISSION CONTROL MODULE (TCM) . >