P013E
O2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 2.
- Generic
- Powertrain
- Generic code
- Low severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 1
- AreaFuel and air metering
- 3E
- FaultThe specific fault in that area
What it means
P013E is a generic code meaning the downstream oxygen sensor (Bank 1, Sensor 2, after the catalytic converter) is slow to react when the mixture changes from rich to lean. The engine control unit monitors how quickly the sensor voltage drops after a rich-to-lean event, such as fuel cut-off on overrun, and sets the code when the response is slower than expected.
Symptoms
- Engine warning light on
- Usually no noticeable change in driving
- Possible slight rise in fuel consumption
- Failed emissions test
- Occasionally a rough idle or hesitation if a related fuel or exhaust fault is present
Possible causes
- Ageing or contaminated downstream oxygen sensor (Bank 1 Sensor 2) with slow responselikely
- Damaged wiring, poor connector contact or corrosion in the sensor circuitpossible
- Exhaust leak near the sensor or upstream of it letting in false airpossible
- Sensor contaminated by oil, coolant or fuel additives, or by siliconepossible
- Ageing catalytic converter altering the exhaust gas signal downstreampossible
- Underlying fuel trim or mixture fault, such as a vacuum leak, leaking injector or fuel pressure problemrare
- Outdated engine control unit software where the manufacturer has a known fault in the monitorrare
How to diagnose
- Read all stored and pending codes and freeze frame data, noting engine load, temperature and fuel trims when the fault was set
- Check for related codes such as catalyst efficiency, fuel trim or misfire codes, and diagnose those first
- Inspect the Bank 1 Sensor 2 wiring and connector for damage, heat melting, water ingress and corrosion
- Check the exhaust for leaks from the manifold to the sensor, including gaskets and joints
- View live data of the downstream sensor voltage and watch how quickly it falls when the throttle is lifted from a steady higher speed or revved and released; compare with the manufacturer's specification
- Check short and long term fuel trims for signs of a lean or rich running condition, and look for vacuum leaks
- Check for signs of oil or coolant consumption that could contaminate the sensor or catalyst
- Check for a manufacturer software update or technical bulletin relevant to the model and engine
How to fix
- Replace the downstream oxygen sensor if its response is confirmed as slow
- Repair or replace damaged wiring or connectors in the sensor circuit
- Repair exhaust leaks and replace faulty gaskets
- Correct any underlying mixture fault such as a vacuum leak or leaking injector, and fix the source of any contamination
- Replace the catalytic converter only if testing proves it is failing
- Update the engine control unit software if an outdated calibration is a known cause for that vehicle
Can I keep driving?
Low severity
The car can normally be driven while you arrange a repair, as this code rarely affects safety or drivability. Do not leave it for long, as the underlying fault could affect emissions, fuel economy or the catalytic converter.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.