Emissions

P013F — Downstream O2 Sensor Slow Response, Lean to Rich (Bank 1 Sensor 2)

Severity: low Safe to drive

What P013F means

The engine control module watches the downstream (post-catalytic converter) oxygen sensor on Bank 1 and compares its signal with what it expects. P013F is set when the sensor's voltage rises too slowly as the exhaust shifts from lean to rich. A healthy rear sensor reacts smoothly but predictably, so a sluggish response points to an aging sensor, a circuit problem or an exhaust leak.

Symptoms

  • Check Engine light on
  • Slightly higher fuel consumption
  • Unstable idle (not always)
  • Occasional hesitation or loss of power
  • Failed emissions inspection

Possible causes

  1. Aged or contaminated Bank 1 Sensor 2 oxygen sensor
  2. Damaged wiring or connector (open, short, corrosion)
  3. Exhaust leak near the sensor
  4. Sensor contamination from oil, coolant or fuel additives
  5. Sensor heater circuit fault
  6. Air-fuel mixture problem upstream of the catalytic converter
  7. Worn catalytic converter (less likely)

How to diagnose

  1. Scan all codes and freeze-frame data and note any fuel trim or misfire codes
  2. Inspect the Bank 1 Sensor 2 harness and connector for chafing, melting, corrosion or a loose fit
  3. Check the exhaust for leaks near the sensor and the catalytic converter
  4. Graph the rear sensor signal live: it should follow load changes rather than stay flat or lazy
  5. Review short- and long-term fuel trims for a lean or rich condition
  6. Test sensor power, ground, and heater resistance and operation
  7. Look for signs of oil or coolant in the exhaust
  8. Clear the code and run a drive cycle to confirm the repair

Common fixes

  • Replace the Bank 1 Sensor 2 oxygen sensor
  • Repair the wiring or replace the connector
  • Fix the exhaust leak
  • Correct the mixture fault or the source of oil or coolant contamination
  • Replace the catalytic converter if testing confirms it is worn out

Questions and answers

What does P013F mean?

The downstream oxygen sensor on Bank 1 reacts too slowly when the exhaust changes from lean to rich. Most often the sensor is simply worn, but the wiring and exhaust should be checked too.

Can I drive with code P013F?

Generally yes for a short time. Fuel use may rise and the car will likely fail an emissions test, so don't wait too long to diagnose it.

Will replacing the sensor fix it?

Not always. Rule out exhaust leaks, wiring damage and mixture problems first, otherwise a new sensor may set the same code again.

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.