AUTOMATIC TRANSMISSION (DIAGNOSTICS)(4AT) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0801 REVERSE INHIBIT CONTROL CIRCUIT

DTC DETECTING CONDITION:

Shift lock solenoid malfunction, open or short reverse inhibitor control circuit

TROUBLE SYMPTOM:

• Gear is shifted from “N” range to “R” range during driving at 20 km/h (12 MPH) or more.

• Gear cannot be shifted from “N” range to “R” range.

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK SHIFT LOCK SOLENOID.

1) Start the integrated unit by force, and check the operation of shift lock solenoid. ()

2) Operate the select lever without depressing the brake pedal.

Can the select lever be operated?

2.CHECK OUTPUT SIGNAL OF INTEGRATED UNIT.

1) Display the following items using Subaru Select Monitor.

• Key warning SW

• Shift position

• P SW

• Stop light switch

2) Step on the brake and shift the select lever to “P” range.

Do the units of measure of items displayed change?

Check the circuits of the items whose values do not change.

3.CHECK HARNESS CONNECTOR BETWEEN BODY INTEGRATED UNIT AND SHIFT LOCK SOLENOID.

Measure the harness resistance between the body integrated unit and chassis ground.

Connector & terminal

(B279) No. 12 — Chassis ground:

Is the resistance 1 MΩ or more?

Repair the short circuit of harness between body integrated unit and shift lock solenoid connector.

4.CHECK HARNESS BETWEEN SHIFT LOCK SOLENOID AND CHASSIS GROUND TERMINAL.

Measure the resistance of harness between shift lock solenoid and chassis ground.

Connector & terminal

(B117) No. 4 — Chassis ground:

Is the resistance less than 1 Ω?

Repair the open circuit of harness between chassis ground and shift lock solenoid connector.

5.CHECK SHIFT LOCK SOLENOID.

Measure the resistance of shift lock solenoid terminals.

Connector & terminal

(B117) No. 3 — No. 4:

Is the resistance between 7 — 21 Ω?

Replace the shift lock solenoid.

6.CHECK OUTPUT SIGNAL OF BODY INTEGRATED UNIT.

1) Connect all connectors.

2) Turn the ignition switch to ON.

3) With the brake pedal depressed, shift the select lever to “D” range.

4) Measure the voltage between body integrated unit and chassis ground.

Connector & terminal

(B279) No. 12 (+) — Chassis ground (−):

Is the voltage 10.5 V or more?

7.CHECK OUTPUT SIGNAL OF BODY INTEGRATED UNIT.

1) Lift up the vehicle.

2) Start the engine.

3) Shift the select lever to “D” range and slowly increase vehicle speed to more than 20 km/h (12 MPH).

NOTE:

A speed difference between front and rear wheels causes the ABS warning light or the VDC warning light to illuminate, but this does not indicate a malfunction. If the warning light is illuminated, clear the ABS and VDC memories of the on-board diagnostic system after completing AT control diagnosis.

4) Measure the voltage between body integrated unit and chassis ground.

Connector & terminal

(B279) No. 12 (+) — Chassis ground (−):

Is the voltage less than 1 V?

The circuit is normal.
If the ATF temperature warning light is flashing, repair the reverse inhibitor control circuit harnesses or connectors.

8.CHECK POOR CONTACT.

Is there poor contact in the reverse inhibitor control circuit?

Repair the poor contact.

Replace the body integrated unit.