OBD-II code family
Oxygen Sensor 1 Pumping-Current Trim Faults (6 codes)
6 related fault descriptions. Use each full code and the exact vehicle service information to identify its circuit, monitored condition, and required tests.
Codes in this family
This is the complete published member list for this guide. Each code retains its own page; shared diagnostic context does not mean that every member has the same test or repair.
- P2626O2 Sensor Pumping Current Trim Circuit/Open (Bank 1 Sensor 1)
- P2627O2 Sensor Pumping Current Trim Circuit Low (Bank 1 Sensor 1)
- P2628O2 Sensor Pumping Current Trim Circuit High (Bank 1 Sensor 1)
- P2629O2 Sensor Pumping Current Trim Circuit/Open (Bank 2 Sensor 1)
- P2630O2 Sensor Pumping Current Trim Circuit Low (Bank 2 Sensor 1)
- P2631O2 Sensor Pumping Current Trim Circuit High (Bank 2 Sensor 1)
What these codes mean
P2626/P2629 compare Bank 1/2 Sensor 1 pumping-current trim circuit/open results. P2627/P2630 identify low results and P2628/P2631 high results. Retain the bank, sensor and condition. Sensor-related trim monitoring is different from the scan tool’s short- or long-term fuel-trim correction.
The historical naming rows do not define one universal calibration circuit. Bosch’s LSU 4.9 datasheet provides a concrete component example with a trimming resistor in its connector module and a dedicated evaluation interface. That product description does not prove that every sensor has the same resistor location, pin assignment, service method or resistance value.
The covered Ford 2024–2025 gasoline summary distinguishes sensor technologies. In its NTK example, trim-low includes open or short-to-ground RL conditions and trim-high includes short-to-battery RL. Low and high therefore cannot be converted into a universal resistance or coolant-contamination diagnosis.
Ford also uses P2626/P2629 for a Bosch air-rationality check separately from the ASIC wire-diagnostic group. A circuit/open label does not establish that a resistor lead is physically broken or that a particular fuel-control fallback has been selected. Identify which monitor set the actual report and preserve any failure suffix.
Confirm the engine’s Bank 1/2 and Sensor 1 identity, fitted part, connector and controller requirements. The identifiers do not say which bank is behind an intake, which lead is longer or where the connector lives. Recent sensor or exhaust work is information to check, not proof of a bad replacement part or a damaged loom.
Fuel trims, bank comparisons and catalyst codes need their own evidence. A moving trim does not identify a substitute calibration; a negative trim does not independently prove rich exhaust or converter damage. Two stored codes do not prove a common cross-short unless the actual circuit and test results support it.
Have the relevant circuit and functional checks performed with the specified protected equipment and connection states. Do not jumper signal/reference terminals, attach an improvised load, cut a wire to hunt for a speculative contamination path, heat a connector or move a live loom beside a hot exhaust. Record the test that confirms the cause before ordering a sensor or controller.
Complete the demonstrated repair, permitted setup and monitor verification, then assess any remaining mixture or catalyst concern separately. Base driving decisions on the actual warnings and symptoms; obtain assistance for severe misfire, overheating, serious running trouble or unsafe response rather than relying on a predicted fallback.
Identify the circuit on your vehicle
Match the full DTC, reporting module, and any failure-type suffix to the service information for your exact year, make, model, engine, and equipment. An identifier alone does not establish installed hardware count, location, connector pinout, or a universal measurement.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.