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OBD-II trouble code

P2631: O2 Sensor Pumping Current Trim Circuit High (Bank 2 Sensor 1)

Application matters: Bank 2 Sensor 1 identifies the monitored position. Supplier construction examples and the Ford NTK/Bosch monitor examples must not be generalized into universal wiring or fallback rules.

P2631 reports a high result in Bank 2 Sensor 1 pumping-current trim monitoring. It does not establish a particular heat-soak failure or explain a Bank 2 catalyst code by itself.

Medium severityPowertrainOxygen SensorAssess symptoms before driving

Quick facts

System
Powertrain
Category
Oxygen Sensor
Severity
Medium severity
Driving guidance
Depends on symptoms and vehicle guidance
Repair cost range
Get a vehicle-specific estimate after diagnosis.
DIY difficulty
Shop recommended

A code alone cannot establish whether driving is safe. Stop safely for a red brake or oil-pressure warning, overheating, severe misfire, stalling, or impaired braking or steering, and follow the owner's manual. Restraints faults can reduce crash protection even when the vehicle runs normally.

Part of a family with 6 codes

P2631 is one of 6 codes covering oxygen sensor 1 pumping-current trim faults. The identifier must be matched to the exact vehicle. Related codes can share a diagnostic approach, but their circuit, failure condition, and required tests can differ.

Read the full guide for this family →

Browse every code in Powertrain, or start from the full code library.

What does P2631 mean?

P2631 identifies a high result in the oxygen-sensor pumping-current trim monitoring associated with Bank 2, Sensor 1. Trim here is the sensor-related monitor terminology; it is not the same thing as the scan tool’s short- or long-term fuel-trim correction.

The cited Ford NTK monitor associates trim-high with a short-to-battery RL condition. It does not support a universal diagnosis of a relaxed terminal, added resistance or a connector that fails only after shutdown.

A Bank 2 catalyst-efficiency result needs its own applicable prerequisites and diagnosis. Correct a demonstrated sensing/circuit or engine concern in the proper order, but do not declare a converter healthy or permanently damaged solely because its code disappears or returns after clearing.

Use the full manufacturer code and suffix, sensor part identity, controller type and failure records. A connector-module calibration resistor exists in the cited Bosch LSU 4.9 product, but there is no universal resistance value, pin assignment, supply relationship or disconnected-reading test that follows from this code family.

Have the sensor-related circuit and relevant functional checks performed with the specified protected equipment and connection states. Do not jumper signal/reference terminals, use an improvised load, cut a lead to search for contamination, apply a heat gun or move wiring around a running hot exhaust. A correct part and undamaged connector are checks to document, not assumptions to turn into a diagnosis.

Ask for the failed test, demonstrated repair and required verification. Fuel-system status, drivability and any mixture/catalyst concerns must be assessed on their own evidence; no universal richer/open-loop fallback or safe travel distance can be read from this code. Follow current warnings and seek assistance for misfire, severe running problems, overheating or unsafe response.

Possible causes

  • A demonstrated fault in the identified Bank 2 Sensor 1 trim/signal connection or circuit
  • A sensor or part/calibration mismatch confirmed against the actual system requirements
  • A receiving-control or relevant functional concern established by the matched monitor diagnosis

Symptoms

  • An engine or emissions warning with P2631
  • Sensor/trim-monitor data requiring interpretation for the installed system
  • Running, fuel-use or related emissions concerns where present rather than a promised fallback

Diagnostic steps

Save the full scan report, code status, and available freeze-frame data before clearing anything. Confirm the reporting module, any failure-type suffix, and the procedure for the exact vehicle. The steps below are an overview; use manufacturer specifications and safety procedures for testing.

  1. 1.Save the full P2631 report, suffix, failure records and recent sensor/exhaust work.
  2. 2.Confirm the actual Bank 2 Sensor 1 part, sensor technology and monitor which set the result.
  3. 3.Have the specified protected circuit and functional checks separate the possible causes.
  4. 4.Verify the demonstrated repair and assess any remaining mixture or catalyst results by their own procedures.

Repair cost

Get a vehicle-specific estimate after diagnosis.

A trouble code alone does not price the repair. Ask the shop to identify the confirmed fault and itemize diagnosis, parts, labor, programming or calibration, and taxes.

Estimate your repair

Run the numbers for your vehicle

Open the Repair Cost Estimator with diagnosis of the reported engine or emissions concern preselected. Adjust labor rate and vehicle category to fit your situation.

Related repairs

These links are planning examples; the code does not confirm that any listed part has failed.

DIY vs shop

A qualified shop is recommended because this can involve manufacturer-grade tooling, training, or certification that most home setups do not have. Ask the technician what testing confirmed the repair.

Related codes

Frequently asked questions

Does a hot-only fault identify a loose terminal?

No. Temperature history is useful evidence but does not identify the mechanism. Avoid heating connectors or manipulating a live loom to provoke the condition.

Does the Bank 2 catalyst code mean this trim fault ruined it?

No. The actual mixture, sensing/circuit concern and catalyst monitor need assessment. The code combination alone does not establish cause, damage or the need for a converter.

Can I drive with P2631?

Use the actual warning and symptoms. The code does not guarantee a fallback, normal operation or a safe distance; arrange assistance for unsafe response, severe misfire, overheating or serious running concerns.

Should I replace the sensor first?

Confirm the correct part and circuit, then ask for the test result supporting replacement. A code title, a cheap part or a normal-looking connector is not a complete diagnosis.

Editorial context

About This Diagnostic Information

These guides provide general diagnostic context. A trouble code records a condition detected by a control module. It does not automatically identify a failed part, and the right diagnostic procedure can vary by vehicle.

References for this guide

  • SAE J2012, April 2002

    Physical page 39 distinguishes the six historical Bank 1/2 Sensor 1 trim circuit/open, low and high names. Naming rows do not specify the installed monitor or repair.

  • BMW published OBD code list, archived

    Physical page 169 supplies the historical code and condition label. Use the actual vehicle information for component identification and diagnosis.

  • Ford 2024–2025 gasoline OBD summary, July 16, 2024 V2

    Physical pages 36–38 distinguish NTK wire diagnostics from the Bosch air-rationality monitor and define the cited trim-low/high examples. The cover identifies 2024–2025 model-year V2, July 16, 2024.

  • Bosch Motorsport LSU 4.9 datasheet, January 27, 2026

    All three pages describe this component’s trimming resistor, controller/evaluation circuit, heater and installation context. The product is an example rather than a vehicle-specific pinout or service test.

Manufacturer service information, technical service bulletins, wiring diagrams, and vehicle-specific procedures should take precedence when available.

AutoLogicTools was founded by Vincent Fisk, an automotive locksmith and shop owner in San Diego with hands-on experience in vehicle keys, immobilizer systems, electrical issues, modules, programming, and diagnostics.