P013D: O2 Sensor Slow Response - Lean to Rich Bank 2 Sensor 2

What it means

Post-cat O2 sensor on bank 2 responds too slowly when mixture transitions from lean to rich. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Bank 2 Sensor 2 monitors oxygen in exhaust after the catalytic converter on the engine's second bank. This code sets when the control module finds that the sensor responds too slowly as exhaust changes from lean to rich.

Common causes

Most likely first.

1. Oxygen sensor aged or sluggish
2. Sensor contaminated by oil, coolant, or fuel
3. Exhaust leak near the sensor
4. Sensor wiring or connector fault

Symptoms

• Check engine light on
• Failed emissions test

How to diagnose it

1. Check freeze-frame data and monitor status to identify the conditions when the Bank 2 lean-to-rich response test failed.
2. Locate Bank 2 Sensor 2 and inspect its wiring, connector, and sensor for heat damage, corrosion, loose terminals, or contamination.
3. Check for an exhaust leak near the Bank 2 downstream sensor and evidence of oil, coolant, or fuel contamination.
4. Graph Bank 2 Sensor 2 data during a warm-engine drive or supported monitor test and assess its response during a lean-to-rich transition.
5. Test the Bank 2 Sensor 2 signal and heater circuits and compare the response with the manufacturer's specification.

Common fixes

• Repair damaged wiring or connector contacts at Bank 2 Sensor 2.
• Repair an exhaust leak near the Bank 2 catalyst outlet.
• Correct a confirmed source of sensor contamination.
• Replace Bank 2 Sensor 2 if its circuit is sound but its lean-to-rich response remains slow.

Can I keep driving?

You can usually drive cautiously if the engine runs smoothly, but the vehicle may fail an emissions test. Stop driving if rough running or a flashing check-engine light appears because continued misfiring can damage the catalyst.