A/T
DTC P0122 - THROTTLE POSITION SENSOR CIRCUIT LOW INPUTDTC DETECTING CONDITION:
- Immediately at fault recognition
TROUBLE SYMPTOM:
- Erroneous idling
- Engine stalls.
- Poor driving performance
CAUTION: After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE and INSPECTION MODE. Refer to How To Clear Diagnostic Trouble Codes.
Wiring Diagram:
WIRING DIAGRAM:
11K1: CHECK CURRENT DATA.
1. Start engine.
2. Read data of throttle position sensor signal using Subaru Select Monitor or OBD-II general scan tool.
NOTE:
- Subaru Select Monitor
For detailed operation procedure, refer to the "READ CURRENT DATA SHOWN ON DISPLAY FOR ENGINE". Refer to Normal Scan Data Values.
- OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II General Scan Tool Instruction Manual.
CHECK: Is the value less than 0.1 V?
YES: Go to step 11K2.
NO: Even if MIL lights up, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector may be the cause.
NOTE: In this case, repair the following:
- Poor contact in throttle position sensor connector
- Poor contact in ECM connector
- Poor contact in coupling connector (B21)
11K2: CHECK INPUT SIGNAL FOR ECM.
Connector & Terminal - [(B136) No.15 (+) - Chassis Ground (-)]:
Measure voltage between ECM connector and chassis ground while throttle valve is fully closed.
CHECK: Is the voltage more than 4.5 V?
YES: Go to step 11K4.
NO: Go to step 11K3.
11K3: CHECK INPUT SIGNAL FOR ECM.
Connector & Terminal - [(B136) No.15 (+) - Chassis Ground (-)]:
Measure voltage between ECM connector and chassis ground.
CHECK: Does the voltage change more than 4.5 V by shaking harness and connector of ECM while monitoring the value with voltage meter?
YES: Repair poor contact in ECM connector.
NO: Contact with Subaru of America (SOA) service.
NOTE: Inspection by Subaru of America's DTM is required, because probable cause is deterioration of multiple parts.
11K4: CHECK INPUT SIGNAL FOR ECM.
Connector & Terminal - [(B136) No.17 (+) - Chassis Ground (-)]:
Measure voltage between ECM connector and chassis ground.
CHECK: Is the voltage less than 0.1 V?
YES: Go to step 11K6.
NO: Go to step 11K5.
11K5: CHECK INPUT SIGNAL FOR ECM. (USING SUBARU SELECT MONITOR.)
Measure voltage between ECM connector and chassis ground.
CHECK: Does the voltage change more than 0.1 V by shaking harness and connector of ECM while monitoring the value with Subaru Select Monitor?
YES: Repair poor contact in ECM connector.
NO: Go to step 11K6.
11K6: CHECK HARNESS BETWEEN ECM AND THROTTLE POSITION SENSOR CONNECTOR.
1. Turn ignition switch to OFF.
2. Disconnect connectors from throttle position sensor.
3. Turn ignition switch to ON.
Connector & Terminal - [(B13) No.4 (+) - Engine Ground (-)]:
4. Measure voltage between throttle position sensor connector and engine ground.
CHECK: Is the voltage more than 4.5 V?
YES: Go to step 11K7.
NO: Repair harness and connector.
NOTE: In this case, repair the following:
- Open circuit in harness between throttle position sensor and ECM connector
- Poor contact in throttle position sensor connector
- Poor contact in ECM connector
- Poor contact in coupling connector (B21)
- Poor contact in joint connector (B83)
11K7: CHECK HARNESS BETWEEN ECM AND THROTTLE POSITION SENSOR CONNECTOR.
1. Turn ignition switch to OFF.
Connector & Terminal - [(B136) No.17 (+) - (E13) No.3]:
2. Measure resistance of harness between ECM connector and throttle position sensor connector.
CHECK: Is the resistance less than 1 Ohm?
YES: Go to step 11K8.
NO: Repair harness and connector.
NOTE: In this case, repair the following:
- Open circuit in harness between throttle position sensor and ECM connector
- Poor contact in ECM connector
- Poor contact in throttle position sensor connector
- Poor contact in coupling connector (B21)
11K8: CHECK HARNESS BETWEEN ECM AND THROTTLE POSITION SENSOR CONNECTOR.
Connector & Terminal - [(E13) No.3 - Engine Ground]:
Measure resistance of harness between throttle position sensor connector and engine ground.
CHECK: Is the resistance less than 10 Ohms?
YES: Repair ground short circuit in harness between throttle position sensor and ECM connector.
NO: Go to step 11K9.
11K9: CHECK POOR CONTACT.
Check poor contact in throttle position sensor connector.
CHECK: Is there poor contact in throttle position sensor connector?
YES: Repair poor contact in throttle position sensor connector.
NO: Replace throttle position sensor.