Faulty bank 2 sensor 1 wideband oxygen sensor (internal pump cell degradation); Damaged or corroded wiring or connector at the sensor or ECM; Exhaust leak upstream of the sensor introducing false air; Contaminated sensor from oil, coolant, or excessive silicone from sealants; ECM internal fault in the pump current control circuit (rare); Low fuel pressure or a vacuum leak causing the sensor to read outside its normal trim range

DTC codes / P26xx · Computer and output circuits / P2630

P2630O2 Sensor Pumping Current Trim Circuit Low (Bank 2 Sensor 1)

P2630 means the engine control module (ECM) has detected that the electrical current trim signal from the bank 2 sensor 1 oxygen sensor's pumping circuit is lower than expected. This sensor is a wideband air-fuel ratio sensor that uses a pump cell to maintain a reference voltage, and the ECM monitors the current needed to do that. A low trim circuit indicates the ECM is seeing a current value below the normal operating range, which can affect fuel control.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Slightly rough idle or hesitation during acceleration
Reduced fuel economy as the ECM may default to a richer air-fuel mixture
Occasional engine surging or stumbling under light throttle
Failed emissions test due to incorrect air-fuel ratio

Common causes, most likely first

Faulty bank 2 sensor 1 wideband oxygen sensor (internal pump cell degradation)
Damaged or corroded wiring or connector at the sensor or ECM
Exhaust leak upstream of the sensor introducing false air
Contaminated sensor from oil, coolant, or excessive silicone from sealants
ECM internal fault in the pump current control circuit (rare)
Low fuel pressure or a vacuum leak causing the sensor to read outside its normal trim range

How to diagnose and fix it

Inspect the sensor wiring and connector for damage, corrosion, or loose pins; repair as needed
Check for exhaust leaks between the engine and the sensor using a smoke test or visual inspection
Measure the sensor heater resistance and compare to manufacturer specifications
Perform a live data scan of the bank 2 sensor 1 pump current trim to see if it is stuck low or erratic
Test the sensor's response to a known air-fuel change (e.g., propane enrichment) to confirm it is lazy or dead
Replace the bank 2 sensor 1 wideband oxygen sensor if diagnostics point to internal failure
Clear codes and verify the repair with a test drive and re-scan

What P2630 really tells you about the sensor

A low pump current trim often means the sensor is reading leaner than actual, so the ECM richens the mixture, which can mask a vacuum leak or fuel delivery issue.
Many technicians replace the sensor without checking for exhaust leaks or wiring issues, which are common causes of this code on higher-mileage vehicles.
The code can be set by a sensor that is simply aged and slow to respond, even if it still switches and does not set a heater circuit code.
On some vehicles, a weak battery or charging system can cause voltage drops that affect the pump current circuit and trigger P2630 intermittently.
P2630 is bank 2 sensor 1, so on V6 and V8 engines it refers to the sensor on the bank that does not include cylinder 1; misidentifying the bank is a frequent mistake.

Can I keep driving with P2630?

You can usually drive the vehicle with P2630 set, but avoid heavy acceleration or towing until it is diagnosed, because the ECM may be running a richer mixture that can damage the catalytic converter over time. If the check engine light starts flashing or you notice severe misfiring, stop driving and seek professional help.

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.