P2626⛽ Fuel and air metering (upstream oxygen sensor)Drive with caution, fix soon

P2626: O2 Sensor Pumping Current Trim Circuit Open B1S1 (Meaning, Causes, Fixes)

Reviewed 2026-10-24 · Based on 2 cited source(s)

What P2626 means

Oxygen sensors measure how much oxygen is left in the exhaust, and the engine computer uses that reading to set the fuel mixture. Sensor 1 is the upstream sensor, mounted before the catalytic converter, and bank 1 is the side of the engine with cylinder 1. OBD-Codes.com explains that the computer can set six codes for the upstream sensor's pumping current trim circuit, P2626 through P2631, depending on the signal it sees, and that P2626 is the 'circuit open' code for bank 1 sensor 1. It lists the code as generic, used by makes including Ford, Kia, Hyundai, Mini, Audi, Volkswagen, Mercedes and BMW. RepairPal describes it more broadly: the code sets when the computer detects a failure of the sensor or of the information it receives from the sensor.

Severity: can I keep driving?

Drive with caution, fix soon

Not an emergency, but get it diagnosed within a reasonable time. RepairPal and OBD-Codes.com both rate P2626 as moderate, and OBD-Codes.com warns it will get worse if it isn't fixed in a timely manner. Expect worse fuel economy and performance, and the check engine light can fail an emissions inspection.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. A faulty upstream oxygen sensor (OBD-Codes.com, RepairPal)
  2. Carbon buildup on the oxygen sensor (OBD-Codes.com)
  3. Damaged wiring or a corroded or damaged connector (OBD-Codes.com, RepairPal)
  4. A blown fuse, on vehicles where the sensor circuit has one (OBD-Codes.com)
  5. An exhaust leak (OBD-Codes.com, RepairPal)
  6. A vacuum leak, or fuel pressure that is too high or too low (OBD-Codes.com)
  7. A faulty engine computer, which is the least likely cause (OBD-Codes.com, RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Read all stored codes and freeze frame data and write them down. Related codes P2627 through P2631 point to the same sensor circuit.
  2. Check for technical service bulletins for your vehicle by year, model and engine. A known problem may have a known fix.
  3. Find the upstream oxygen sensor (before the catalytic converter) on bank 1 and inspect its wiring for rubbing, bare wires or burn spots, especially near hot exhaust parts.
  4. Check the sensor connector for a secure fit, corrosion and damaged pins.
  5. Check any fuse that feeds the sensor circuit, if your vehicle has one.
  6. With the engine running, listen and look for exhaust leaks near the sensor and for vacuum leaks on the engine.
  7. Clear the code and drive to see if it comes back. Further voltage, continuity and fuel pressure tests need a multimeter, a gauge and the specs for your vehicle.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • The wiring, connector and fuse look fine but the code keeps coming back
  • You need fuel pressure or circuit tests and don't have the gauge, multimeter or vehicle wiring data
  • The sensor is seized in the exhaust or hard to reach
  • You need the light off for an inspection deadline

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P2626 serious?

It's moderate. Both RepairPal and OBD-Codes.com rate it that way. The car usually still drives, but fuel economy and performance can suffer, and OBD-Codes.com warns the problem will progress if it isn't fixed.

Which oxygen sensor is bank 1 sensor 1?

Sensor 1 is the upstream sensor, before the catalytic converter. Bank 1 is the side of the engine with cylinder 1. On a 4-cylinder engine there is only one bank.

What's the difference between P2626 and P2627 to P2631?

OBD-Codes.com says all six codes cover the upstream oxygen sensor's pumping current trim circuit. Which one sets depends on the signal the engine computer sees, and P2626 is the 'circuit open' version for bank 1 sensor 1.

Do the sources agree on P2626?

Mostly. Both rate it moderate and list the oxygen sensor, wiring, exhaust leaks and the engine computer. OBD-Codes.com says the code sets when the circuit is open and adds a blown fuse, carbon buildup, vacuum leaks and fuel pressure that is too high or too low. RepairPal gives a broader explanation, that the computer has detected a failure of the sensor or its information, and names oxygen sensor replacement as the common repair.

How much does it cost to fix P2626?

Neither source gives a repair cost. It depends on whether it's a wire, a connector, a leak or the sensor itself, so get a written estimate after diagnosis.

Sources

  1. OBD-Codes.com: P2626 O2 Sensor Pumping Current Trim Circuit/Open Bank 1 Sensor 1 (John Ingalls, former service manager and Air Force mechanic)
  2. RepairPal: P2626 O2 Sensor Pumping Current Trim Circuit/Open (rated Moderate)

Last reviewed 2026-10-24. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.