What the P2626 Code Means?
If a P2626 code appears, your vehicle's ECM has received a voltage signal from oxygen sensor number 1
pumping current trim circuit for bank 1 that is not within the accepted variances. This typically means the
engine block contained the number 1 cylinder is impacted and a fault has been found in the sensor ahead
of the catalytic converter (upstream sensor or sensor 1). After reaching normal operating temperature and
the ECM reaches closed-loop operations, upstream heater oxygen sensor readings should vary consistently
from 100 to 900 mill volts. It could also be due to an oxygen sensor reading being lower than allowed
variances. When the voltage signal variance exceeds 10%, either high or low, the ECM will store a P2626
What Causes the P2626 Code?
1. Faulty O2 Sensor
2. Carbon Build up on O2 Sensor
3. Blown fuse (if applicable)
4. Fuel pressure too high
5. Fuel pressure too low
6. Vacuum leak on the engine
7. Excessive exhaust leak
What are the Symptoms of the P2626 Code?
These could include a lean or rich condition in the engine, decreased fuel efficiency, black smoke from the
tailpipe, and an illuminated service engine soon lamp.
Common Mistakes when Diagnosing the P2626 Code?
Technicians report replacement of oxygen sensors, when lean or rich engine conditions are the cause of
incorrect readings, is fairly common. Replacement of the incorrect oxygen sensor is also a possibility.
What Repairs can fix the P2626 Code?
Replace oxygen sensor 1 bank 1
Replace or repair damaged or defective wiring harnesses
Replace or repair any damaged wires and electrical connectors
Replace any faulty or blown fuses for the oxygen sensor
Too low or too excessive fuel pressure
Repair or replace any damaged hoses