Aging or contaminated downstream oxygen sensor (bank 2 sensor 2) that responds slowly; Exhaust leaks ahead of the sensor letting outside air pulse past it; Wiring damage or corroded connector pins at the sensor or harness; An exhaust leak at the manifold or downpipe on bank 2; A lazy upstream sensor on bank 2 skewing the mixture the downstream sensor sees; A restricted or failing catalytic converter on bank 2 that changes exhaust flow; Engine misfire or rich running condition on bank 2 contaminating the sensor

DTC codes / P01xx · Fuel and air metering / P013C

P013CO2 Sensor Slow Response - Rich to Lean Bank 2 Sensor 2

Q: What does code P013C mean?

O2 Sensor Slow Response - Rich to Lean Bank 2 Sensor 2. P013C means the downstream oxygen sensor on bank 2 is taking too long to switch from a rich to a lean signal, so the engine computer has flagged its response as sluggish. The computer watches the sensor voltage and expects it to change quickly when the exhaust mixture changes; this code sets when that transition is slower than the calibrated limit.

P013C means the downstream oxygen sensor on bank 2 is taking too long to switch from a rich to a lean signal, so the engine computer has flagged its response as sluggish. The computer watches the sensor voltage and expects it to change quickly when the exhaust mixture changes; this code sets when that transition is slower than the calibrated limit.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
A slight drop in fuel economy that develops gradually
Occasional rough idle or hesitation when the engine is cold
Failed emissions test due to readiness monitors not completing
In rare cases, a faint sulfur or rotten egg smell from the exhaust

Common causes, most likely first

Aging or contaminated downstream oxygen sensor (bank 2 sensor 2) that responds slowly
Exhaust leaks ahead of the sensor letting outside air pulse past it
Wiring damage or corroded connector pins at the sensor or harness
An exhaust leak at the manifold or downpipe on bank 2
A lazy upstream sensor on bank 2 skewing the mixture the downstream sensor sees
A restricted or failing catalytic converter on bank 2 that changes exhaust flow
Engine misfire or rich running condition on bank 2 contaminating the sensor

How to diagnose and fix it

Scan all stored and pending codes, then record freeze-frame data for P013C
Inspect the bank 2 sensor 2 wiring and connector for corrosion, chafing, or loose pins
Perform a visual and smoke test of the bank 2 exhaust for leaks ahead of the sensor
Graph the bank 2 sensor 2 voltage on a scan tool and compare its switching rate to the bank 1 sensor 2
Check fuel trims and misfire counters on bank 2 to rule out an engine condition skewing the sensor
Replace the bank 2 sensor 2 only after confirming the sensor itself is slow and not the wiring or exhaust
Clear codes and complete a drive cycle to verify the monitor passes

Why a slow sensor is not always the sensor

A small exhaust leak before the downstream sensor can mimic a slow sensor because outside air pulses past the tip and delays the voltage change.
A lazy upstream sensor on the same bank can make the downstream sensor look slow even when the downstream unit is healthy.
Many technicians replace the downstream sensor first and later find corroded connector pins or a chafed harness were the real cause.
This code can set after a recent sensor replacement if the new sensor is not the correct type or the connector is not fully seated.
A failing catalytic converter on bank 2 can change exhaust flow enough to slow the downstream sensor response without setting a converter efficiency code yet.

Can I keep driving with P013C?

You can usually keep driving with P013C because it does not affect engine safety, but avoid ignoring it for months since a worsening exhaust or sensor fault can raise emissions and fuel consumption. Have the exhaust and wiring checked before replacing parts, and do not tow a heavy load until the cause is confirmed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.