OBD-II Generic Error Code P2629: How to Fix It

Q: What does P2629 mean on my vehicle?

P2629 means the engine control module (ECM) has detected a fault in the pumping current trim circuit for the upstream oxygen sensor on Bank 2. This is the air-fuel ratio (wideband) sensor that monitors exhaust gases before the catalytic converter on the side of the engine that does not contain cylinder #1. The 'open' designation indicates the circuit may be broken or the sensor's internal pumping cell has failed.

Q: Can I drive with a P2629 code?

You can drive short distances with a P2629 code, but it is not recommended for extended driving. Without a functioning Bank 2 upstream oxygen sensor, the ECM cannot accurately control the air-fuel mixture on that bank. This leads to reduced fuel efficiency, increased emissions, possible rough running, and over time can cause damage to the catalytic converter due to an uncorrected rich or lean condition.

Q: How much does it cost to fix a P2629 code?

If the fix is a wiring repair, costs can range from $50–$150 in parts and labor for simple connector or wire repairs. Replacing the wideband oxygen sensor itself typically costs $100–$400 depending on the vehicle make and model, with OEM sensors at the higher end. Labor at a shop to diagnose and replace the sensor generally runs $75–$200 on top of parts, bringing a full repair to anywhere from $150–$600 in a shop setting.

Q: Is P2629 the same as a standard O2 sensor fault?

Not exactly. P2629 specifically relates to the pumping current trim circuit inside a wideband (air-fuel ratio) sensor, which is a more sophisticated and expensive sensor than a traditional narrowband O2 sensor. Wideband sensors measure a much broader range of air-fuel ratios and have an internal pumping cell and Nernst cell. A standard narrowband O2 sensor fault code (like P0141 or P0161) usually refers to heater or voltage response issues on a simpler sensor design.

Q: Will P2629 cause a failed emissions test?

Yes, in most cases a stored P2629 code will cause a failed emissions inspection. Most emissions test protocols check for active trouble codes and will fail any vehicle with a stored fault code related to emission control systems, including oxygen sensor faults. You must resolve the underlying problem and complete a full drive cycle so all monitors run to 'ready' status before taking the vehicle for an emissions test.

Abstract

OBD-II error code P2629 indicates a fault in the oxygen sensor pumping current trim circuit for Bank 2, Sensor 1 — the upstream O2 sensor on the side of the engine that does NOT contain cylinder #1. This code typically means the ECM/PCM has detected an open circuit or an out-of-range signal from the wideband (air-fuel ratio) sensor's internal pumping cell, which is critical for precise fuel mixture control. Left unresolved, this fault can cause poor fuel economy, failed emissions tests, rough running, and potential catalytic converter damage.