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.
Medium severity. Can I keep driving?Yes, you can normally drive in moderation, but get it repaired soon: you will use more fuel and the catalytic converter can be damaged over time.
Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank. Sensor 1 is the oxygen sensor before the catalytic converter.
Symptoms
- Check engine light
- Fuel control falls back to open loop on bank 1
- Slightly higher fuel consumption or rough idle
Most likely causes
- Front wide-band probe defective (trim resistor, pump cell or heater damage)
- Trim line broken or pin pushed back in the six-pin probe connector
- Moisture or corrosion in the probe connector raising the measured resistance
- Engine software requiring an update after probe replacement (some makes)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2626 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 6: Control modules and outputs
- 26: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2626?
Yes, you can normally drive in moderation, but get it repaired soon: you will use more fuel and the catalytic converter can be damaged over time.
What causes code P2626?
The most common causes are: front wide-band probe defective (trim resistor, pump cell or heater damage); trim line broken or pin pushed back in the six-pin probe connector; moisture or corrosion in the probe connector raising the measured resistance.
Related codes
- 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)
- P2237O2 Sensor Positive Current Control Circuit/Open (Bank 1 Sensor 1)
- P2243O2 Sensor Reference Voltage Circuit/Open (Bank 1 Sensor 1)
- P2195O2 Sensor Signal Biased/Stuck Lean (Bank 1, Sensor 1)
- P0130O2 Sensor Circuit Bank 1 Sensor 1
Sources
- gsi.ext.gm.com: 23OBDG03A Part2
- static.nhtsa.gov: MC 10074004 2280
- saabwisonline.com: dtc p2237 p2239 p2243 p2251 or p2626
- fordservicecontent.com: OBD Operations Summary Gasoline 2020 2023
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.