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

WARNING: This page is about a different car, the 2020 Subaru Impreza. 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 (IMPREZA MODEL)>CVT CONTROL SYSTEM .

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) (IMPREZA MODEL)>BASIC DIAGNOSTIC PROCEDURE .

Courtesy of SUBARU OF AMERICA, INC.

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) (IMPREZA MODEL)>DATA MONITOR .
Is the display of the corresponding range [ON]?

Yes : Go to 6.

No : Go to 2.
CHECK HARNESS .
1. Turn the ignition switch to OFF.
2. Disconnect the TCM connector.
3. Disconnect the inhibitor switch connector.
4. Measure the resistance of the harness between TCM connector and inhibitor switch connector.
  Connector & terminal
  
  (T10) No. 38 - (T7) No. 2:
  
  (T10) No. 37 - (T7) No. 5:
  
  (T10) No. 36 - (T7) No. 3:
  
  (T10) No. 35 - (T7) No. 4:
Is each resistance less than 1 Ω?

Yes : Go to 3.

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

Connector & terminal

(T7) No. 1 - Transmission ground:

Is the resistance less than 1 Ω?

Yes : Go to 4.

No : Repair the open circuit of 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 5.

No : Replace the inhibitor switch. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>INHIBITOR SWITCH .
CHECK HARNESS .
1. Turn the ignition switch to ON.
2. Measure the voltage between inhibitor switch connector and chassis ground.
  Connector & terminal
  
  (T7) No. 2 (+) - Chassis ground (-):
  
  (T7) No. 5 (+) - Chassis ground (-):
  
  (T7) No. 3 (+) - Chassis ground (-):
  
  (T7) No. 4 (+) - Chassis ground (-):
Is each voltage less than 1 V?

Yes : Go to 6.

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 (TR580 IMPREZA)>TRANSMISSION CONTROL MODULE (TCM) .