Front Oxygen Sensor Circuit Malfunction Short
2000-2004 Subaru Outback 2.5L H4 🇨🇦
Description
The PCM has detected a short circuit condition in the front oxygen sensor circuit. The sensor signal is shorted to ground or to the reference voltage, causing an incorrect fuel mixture reading.
Symptoms
- Check Engine Light
- Engine runs rich or lean depending on short direction
- Poor fuel economy
- Rough idle
- Failed emissions
Common Causes
- O2 sensor wiring shorted to ground or voltage
- Internal O2 sensor failure
- Wiring chafed against exhaust or engine components
- Water intrusion in O2 sensor connector
- Heat-damaged wiring insulation
Diagnostic Steps
- Check O2 sensor voltage on scan tool (stuck high or low indicates short)
- Inspect wiring for chafing or exposed conductors
- Test for shorts to ground and to voltage in sensor circuit
- Check connector for water intrusion
- Disconnect sensor and recheck circuit
Repair Notes
Repair the shorted wiring or replace the front O2 sensor if internally shorted.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1131 on Other Vehicles
Common Questions
What does code P1131 mean on a 2000-2004 Subaru Outback?
P1131 stands for "Front Oxygen Sensor Circuit Malfunction Short". The PCM has detected a short circuit condition in the front oxygen sensor circuit. The sensor signal is shorted to ground or to the reference voltage, causing an incorrect fuel mixture reading.
What are the symptoms of P1131 on a Subaru Outback?
Common symptoms of P1131 include: Check Engine Light, Engine runs rich or lean depending on short direction, Poor fuel economy, Rough idle, Failed emissions.
What causes P1131 on a 2000-2004 Subaru Outback?
Common causes of P1131 include: O2 sensor wiring shorted to ground or voltage, Internal O2 sensor failure, Wiring chafed against exhaust or engine components, Water intrusion in O2 sensor connector, Heat-damaged wiring insulation.