DTC P0708: Transmission Range Sensor "A" Circuit High: Notes

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.

1. -

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Shift characteristics are erroneous.
The range position of the select lever and the position of shift indicator display do not match.

Wiring diagram:

CVT control system Ref. to WIRING SYSTEM>CVT CONTROL SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Use CHECK BOARD when measuring the TCM terminal voltage and resistance.
After servicing or replacing faulty parts, perform the last step of the basic diagnostic procedure. Ref. to TRANSMISSION (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE

CHECK INPUT SIGNAL FOR TCM .
1. Turn the ignition switch to ON.
2. Move the select lever to each range, and read the data of [P Range], [R Range Signal], [N Range], [D Range Signal] in the [Data Monitor] of [Transmission] using the Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS)>DATA MONITOR
Is the display of the corresponding range [ON]?

Yes : Go to 7.

No : Go to 2.
CHECK HARNESS .
1. Turn the ignition switch to OFF.
2. Disconnect the TCM connector.
3. Disconnect the transmission connector.
4. Measure the resistance of harness between TCM connector and transmission connector.
  Connector & terminal
  
  (B67) No. 38 - (E33) No. 4:
  
  (B67) No. 37 - (E33) No. 5:
  
  (B67) No. 36 - (E33) No. 9:
  
  (B67) No. 35 - (E33) No. 10:
Is each resistance less than 1 Ω?

Yes : Go to 3.

No : Repair the open circuit of body harness.
CHECK HARNESS .
Measure the resistance of harness between inhibitor switch connector and transmission ground.

Connector & terminal

(T31) No. 1 - Transmission ground:

Is the resistance less than 1 Ω?

Yes : Go to 4.

No : Repair the open circuit of harness.
CHECK HARNESS .
1. Disconnect the inhibitor switch connector.
2. Measure the resistance of harness between transmission connector and inhibitor switch connector.
  Connector & terminal
  
  (T2) No. 4 - (T31) No. 2:
  
  (T2) No. 5 - (T31) No. 5:
  
  (T2) No. 9 - (T31) No. 3:
  
  (T2) No. 10 - (T31) No. 4:
Is each resistance less than 1 Ω?

Yes : Go to 5.

No : Repair the open circuit of transmission harness.
CHECK INHIBITOR SWITCH .
Move the select lever to each range, and measure the resistance between inhibitor switch terminals.

Connector & terminal

No. 2 - No. 1:

No. 5 - No. 1:

No. 3 - No. 1:

No. 4 - No. 1:

Is the resistance of the corresponding range less than 1 Ω?

Yes : Go to 6.

No : Replace the inhibitor switch. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>INHIBITOR SWITCH
CHECK HARNESS .
1. Turn the ignition switch to ON.
2. Measure the voltage between each connector and chassis ground.
  Connector & terminal
  
  Transmission connector (E33 side)
  
  (E33) No. 4 (+) - Chassis ground (-):
  
  (E33) No. 5 (+) - Chassis ground (-):
  
  (E33) No. 9 (+) - Chassis ground (-):
  
  (E33) No. 10 (+) - Chassis ground (-):
  
  Transmission connector (T31 side)
  
  (T31) No. 2 (+) - Chassis ground (-):
  
  (T31) No. 5 (+) - Chassis ground (-):
  
  (T31) No. 3 (+) - Chassis ground (-):
  
  (T31) No. 4 (+) - Chassis ground (-):
Is each voltage less than 1 V?

Yes : Go to 7.

No : Repair the harness which outputs 1 V or more.
CHECK FOR POOR CONTACT .
Is there poor contact between TCM, inhibitor switch, transmission ground?

Yes : Repair the poor contact.

No : Replace the TCM. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION CONTROL MODULE (TCM)