P2C63O2 Sensor Pumping Current Trim Circuit Low Bank 1 Sensor 3
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2C63 reports that the oxygen value from the third exhaust sensor of bank 1 has dropped below its physically possible minimum. Despite the trim wording, GM uses it on the 3.0L Duramax diesel for the O2 signal of NOx sensor 3, which sits behind the second catalyst: table 25OBDG04B (2025) fails a reading under -6 percent in 100 of 200 samples on a 25 ms task, with the engine running, supply above 11 V and the sensor ready; Type B, MIL after two trips. GM's PIT5751C and bulletin 21-NA-149 name P2C63 among many codes on 2020-21 Silverado, Sierra, Tahoe, Yukon and Escalade with the 3.0L LM2; the cause was an engine harness rubbed through above the generator or shorted against the clamp of the crankcase-pressure-regulator hose. P2C64 is the high side, P23AE the NOx circuit low code of this sensor.
- What you may notice
- MIL on after two trips
- On the GM LM2 often many other codes, rough running or blown fuses when the harness is damaged
- Aftertreatment monitors not completing
- Likely causes
- LikelyEngine harness chafed or shorted (GM 3.0L LM2 - at the generator or the crankcase pressure regulator clamp)
- PossibleThird exhaust sensor (on GM diesels NOx sensor 3) reporting an implausibly low O2 value
- RareCorroded or loose sensor connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.