Cause
Exhaust leak before the sensor
A leak upstream of an oxygen sensor draws air in between exhaust pulses, so the sensor reports oxygen that never passed through the engine. The module then adds fuel to correct a lean condition that does not exist.
The leak is frequently at a manifold stud or a flexible section rather than anywhere obvious.
Typically a moderate job.
Codes this can cause (54)
Codes where this is a likely explanation first, rather than merely a possible one.
- P0130 O2 Sensor Circuit — Bank 1 Sensor 1 Likely for this code Moderate
- P0131 O2 Sensor Circuit Low Voltage — Bank 1 Sensor 1 Likely for this code Moderate
- P0137 O2 Sensor Circuit Low Voltage — Bank 1 Sensor 2 Likely for this code Moderate
- P0143 O2 Sensor Circuit Low Voltage — Bank 1 Sensor 3 Likely for this code Moderate
- P0150 O2 Sensor Circuit — Bank 2 Sensor 1 Likely for this code Moderate
- P0151 O2 Sensor Circuit Low Voltage — Bank 2 Sensor 1 Likely for this code Moderate
- P0157 O2 Sensor Circuit Low Voltage — Bank 2 Sensor 2 Likely for this code Moderate
- P0163 O2 Sensor Circuit Low Voltage — Bank 2 Sensor 3 Likely for this code Moderate
- P0420 Catalyst System Efficiency Below Threshold — Bank 1 Likely for this code Moderate
- P0421 Catalyst 1 Efficiency Below Threshold Bank 1 Likely for this code Moderate
- P0422 Catalyst 2 Efficiency Below Threshold Bank 1 Likely for this code Moderate
- P0430 Catalyst System Efficiency Below Threshold — Bank 2 Likely for this code Moderate
- P0431 Catalyst 1 Efficiency Below Threshold Bank 2 Likely for this code Moderate
- P0432 Catalyst 2 Efficiency Below Threshold Bank 2 Likely for this code Moderate
- P2096 Post Catalyst Fuel Trim System Too Lean — Bank 1 Likely for this code Moderate
- P2098 Post Catalyst Fuel Trim System Too Lean — Bank 2 Likely for this code Moderate
- P2179 System Too Lean Off Idle Bank 2 Likely for this code Moderate
- P2195 O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1 Likely for this code Moderate
- P2197 O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 1 Likely for this code Moderate
- P2270 O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 2 Likely for this code Moderate
- P2272 O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 2 Likely for this code Moderate
- P2274 O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 3 Likely for this code Moderate
- P2276 O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 3 Likely for this code Moderate
- P2297 O2 Sensor Out of Range During Deceleration Bank 1 Sensor 1 Likely for this code Moderate
- P2298 O2 Sensor Out of Range During Deceleration Bank 2 Sensor 1 Likely for this code Moderate
Information, not instruction
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