P2626O2 Sensor Pumping Current Trim Circuit/Open (Bank 1 Sensor 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Wide-band lambda probes such as the Bosch LSU 4.9 carry a calibration resistor in their plug; the engine module uses it to scale the pumping current. P2626 says this trim path at the front probe of bank 1 looks open. Makers detect it differently: GM's 2023 tables let the sensor chip measure the resistor after each start and fail an LSU 4.9 above 379.5 ohms (NGK ZFAS-U2: above 4,644 ohms), type B. VW's 2014 data books flag a probe signal above 4.81 V, and the 2010 Saab 9-5 applies that limit during fuel cut-off (type B). Ford's Bosch-equipped engines run an air test in overrun and fail a pump current above 3.09 mA held for 2 s. Ford's TSB 17-2124 for the 3.5 L EcoBoost in Explorer and F-150 (2015-17) cures it with a new probe. Low and high faults are P2627/P2628; bank 2 is P2629.
- What you may notice
- Check engine light
- Fuel control falls back to open loop on bank 1
- Slightly higher fuel consumption or rough idle
- Likely causes
- LikelyFront wide-band probe defective (trim resistor, pump cell or heater damage)
- PossibleTrim line broken or pin pushed back in the six-pin probe connector
- RareMoisture or corrosion in the probe connector raising the measured resistance
- RareEngine software requiring an update after probe replacement (some makes)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.