Emissions

P014A — O2 Sensor Delayed Response, Rich to Lean (Bank 2 Sensor 2)

Severity: medium Safe to drive

What P014A means

The engine computer monitors the Bank 2 downstream (post-catalyst) oxygen sensor and compares its signal with what it expects. When the mixture suddenly goes lean, such as during deceleration fuel cutoff, the sensor voltage should drop quickly. P014A is set when that drop is too slow. The cause may be the sensor itself, its wiring, an exhaust leak, or a mixture problem.

Symptoms

  • Check Engine light on
  • Worse fuel economy
  • Slightly reduced performance
  • Rough or unstable idle
  • Unusual exhaust smell
  • Failed emissions test

Possible causes

  1. Aged or contaminated Bank 2 downstream O2 sensor
  2. Damaged wiring or corroded connector at the sensor
  3. Exhaust leak near or ahead of the sensor
  4. Sensor heater circuit fault
  5. Worn or inefficient catalytic converter
  6. Mixture problem on Bank 2, such as injectors, vacuum leaks, or fuel pressure

How to diagnose

  1. Read freeze frame data and check for other codes involving fuel trim, misfires, or the catalyst
  2. Inspect the sensor connector and harness for damage, oil, corrosion, and chafed insulation
  3. Look for exhaust leaks at and ahead of the sensor, such as soot at joints or hissing
  4. Compare the sensor's live data with the Bank 1 downstream sensor at different loads
  5. Review short and long term fuel trims for Bank 2 at idle and under load
  6. Test heater resistance and supply voltage against the wiring diagram
  7. Watch the sensor voltage when you lift off the throttle sharply; it should fall quickly
  8. Evaluate catalytic converter condition if the sensor and wiring check out

Common fixes

  • Replace the Bank 2 downstream oxygen sensor
  • Repair the wiring or replace the connector
  • Fix the exhaust leak
  • Correct the underlying mixture fault, such as injectors, vacuum leaks, or fuel pressure
  • Replace the catalytic converter if testing confirms it has failed

Questions and answers

What does P014A mean?

The Bank 2 downstream oxygen sensor is too slow to show the mixture going from rich to lean. The usual culprits are the sensor, its wiring, or an exhaust leak.

Can I drive with P014A?

Generally yes, but don't put off diagnosis. Extra fuel use and a wrong mixture can eventually damage the catalytic converter.

Should I replace the sensor right away?

Not before checking the wiring, connector, exhaust leaks, and fuel trims. A new sensor won't fix the code if the cause lies elsewhere.

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.