Emissions

P013C — O2 Sensor Slow Response, Rich to Lean (Bank 2 Sensor 2)

Severity: medium Safe to drive

What P013C means

P013C means the downstream (post-catalyst) oxygen sensor on Bank 2 is responding too slowly when exhaust changes from rich to lean. The engine computer compares how fast the signal changes against an expected rate and finds it too sluggish. This sensor normally reads fairly steady and is used to monitor the catalytic converter and fine-tune fueling.

Symptoms

  • Check Engine light on
  • Reduced fuel economy
  • Sluggish performance
  • Rough or unstable idle
  • Poor throttle response
  • Often no symptom other than the warning light

Possible causes

  1. Aged, contaminated or worn Bank 2 downstream O2 sensor
  2. Damaged wiring or corroded connector at the sensor
  3. Sensor heater circuit fault
  4. Exhaust leak near the sensor
  5. Failing catalytic converter
  6. Mixture problem upstream (injectors, vacuum leak, fuel pressure)

How to diagnose

  1. Scan for codes and freeze-frame data, noting any misfire or fuel trim codes
  2. Inspect the Bank 2 Sensor 2 harness and connector for breaks, melting, moisture and corrosion
  3. Test the heater circuit: heater resistance and power supply
  4. Look for exhaust leaks ahead of and around the sensor
  5. Review short and long term fuel trims for mixture faults
  6. Graph the sensor signal on a scan tool while snapping the throttle open and closed
  7. Compare the downstream signal with the upstream sensor and judge catalyst condition
  8. After repair, clear the code and run a verification drive cycle

Common fixes

  • Replace the Bank 2 downstream oxygen sensor
  • Repair the wiring or connector
  • Fix the exhaust leak
  • Correct the underlying mixture problem
  • Replace the catalytic converter if it is confirmed faulty

P013C on different brands

Ford · manuals
Ford shows this as P013C:00, describing a slow rich-to-lean response on Bank 2 Sensor 2; it identifies the monitor condition detected, not a confirmed failed part.

Questions and answers

Can I drive with code P013C?

Usually yes for a short time, since the car remains drivable. Don't put off the repair, though, to avoid wasted fuel and possible catalytic converter damage.

Do I always need a new oxygen sensor?

No. Check the wiring, connector, exhaust leaks and fuel trims first. Replace the sensor if those are fine and its signal is still slow.

Where is Bank 2 Sensor 2?

It is the sensor after the catalytic converter on the side of the engine that doesn't contain cylinder 1. Exact location varies by model, so check the exhaust layout for your vehicle.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.