Emissions

P014B — Slow Rear O2 Sensor Response, Lean to Rich (Bank 2 Sensor 2)

Severity: low Safe to drive

What P014B means

The Bank 2 Sensor 2 oxygen sensor sits after the catalytic converter and helps the control module judge how well the converter is working. When the mixture briefly shifts from lean to rich, the sensor signal should rise quickly. With P014B, the module sees that the signal changes too slowly. Bank 2 is the side of the engine that does not contain cylinder 1.

Symptoms

  • Check Engine light on
  • Possible increase in fuel consumption
  • Rough or unstable idle (not always)
  • Occasional hesitation or surging
  • Often no noticeable symptoms besides the light

Possible causes

  1. Aged or contaminated Bank 2 Sensor 2 oxygen sensor
  2. Damaged sensor wiring or connector: open, short or corrosion
  3. Exhaust leak upstream of or near the sensor
  4. Sensor heater circuit fault
  5. Reduced catalytic converter efficiency
  6. Upstream mixture problem such as a vacuum leak, faulty injectors or fuel pressure issue

How to diagnose

  1. Scan for codes and freeze frame data, and note any misfire, fuel trim or other sensor codes
  2. Watch the Bank 2 Sensor 2 signal in live data; it should react quickly and clearly to rich and lean changes
  3. Check short and long term fuel trims on both banks for a lean or rich condition
  4. Inspect the sensor connector and wiring for damage, oil, moisture, corrosion and chafing
  5. Look for exhaust leaks ahead of and around the sensor
  6. Test heater power, ground and resistance following the wiring diagram
  7. Evaluate the catalytic converter and compare upstream and downstream sensor signals
  8. After repair, clear the code and confirm it does not return

Common fixes

  • Replace the Bank 2 Sensor 2 oxygen sensor
  • Repair wiring or replace the connector
  • Fix the exhaust leak
  • Correct the underlying mixture problem (vacuum leak, injectors, etc.)
  • Replace the catalytic converter if it is confirmed faulty

Questions and answers

What does P014B mean?

The control module found that the Bank 2 downstream O2 sensor reacts too slowly when the mixture goes from lean to rich. The cause can be the sensor, its wiring, an exhaust leak or a mixture problem.

Can I drive with P014B?

Yes, usually, but get it fixed soon. Otherwise you may see worse fuel economy and fail an emissions inspection.

Do I always need a new sensor for P014B?

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

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.