P0136

DTC PO136
REAR OXYGEN SENSOR CIRCUIT MALFUNCTION (RO2 - Volts)

Description
- In order to monitor purifying efficiency of the catalyst the rear oxygen sensor sends a signal to the Engine Control Module (ECM).
- Refer to DTC P0130 front oxygen sensor circuit Malfunction.
DTC Detecting Condition
Two consecutive trips with fault











1. Check DTC P0130 on display.
[CHECK]: Check that Subaru Select Monitor or the OBD-II General Scan Tool shows P013O.
[YES]: Go to step 2.
[NO]: Go to step 3.

2. Check failure cause of P0130.
- Perform the Step 1 of DTC P0130.
[CHECK]: Is the failure cause of P0130 in the fuel system?
[YES]: Check fuel system. In this case, inspection of P0136 is not necessary.
[NO]: Go to step 3.

3. Check rear oxygen sensor data.





a. Turn Ignition switch to "OFF".
b. Connect Subaru Select Monitor or OBD-II General Scan Tool to Data Link Connector.
c. Start the Engine, and turn Subaru Select Monitor or OBD-II General Scan Tool switch to "ON".
d. Warm-up the engine until engine coolant temperature is above 70°C (160°F), and keep the engine speed at 2,000 rpm to 3,000 rpm for two minutes.
e. Read data on Subaru Select Monitor or OBD-II General Scan Tool.

Subaru Select Monitor
- Designate mode using function key.
- Function mode: F16.

[CHECK] Did the indicated data fluctuate?
[YES]: Go to step 5.
[NO]: Go to next [CHECK].

[CHECK]: Is the indicated data fixed at 0.3 ± 0.1 Volt?
[YES]: Go to step 4.
[NO]: Replace rear oxygen sensor.

OBD-II General Scan Tool
- For detailed operation procedures, refer to the OBD-II General Scan Tool Instruction Manual.

4. Check harness.
a. Turn Ignition switch to "OFF".
b. Disconnect connector from rear oxygen sensor.
c. Turn ignition switch to "ON".





d. Measure voltage between rear oxygen sensor harness connector and body.
[CHECK]: Connector & terminal:
(T6) No. 4 - Body/0.2 Volt, or more.
[NO]: Repair harness and connector.

NOTE: In this case the following are the possible causes.
- Open circuit of harness between rear oxygen sensor and ECM connector.
- Poor contact in rear oxygen sensor connector.
- Poor contact in ECM connector.
- Poor contact in rear oxygen sensor connecting harness connector.

[YES]: Replace rear oxygen sensor.

5. Check exhaust system.
[CHECK]: Check the following items.
- Looseness of installation portions.
- Damage (crack, holes etc.) of parts.
- Looseness and opening of parts between front oxygen sensor and rear oxygen sensor.
[YES]: Repair or replace faulty parts.
[NO]: Replace rear oxygen sensor.