P2C64 code meaning
O2 Sensor Pumping Current Trim Circuit High Bank 1 Sensor 3
Powertrain system Generic code P2Cxx codes Check engine light
What P2C64 means
P2C64 is the high-side partner of P2C63: the oxygen reading attributed to sensor 3 of bank 1 climbs above what the probe can physically deliver. On GM's 3.0L Duramax diesel the value comes from NOx sensor 3 behind the second catalyst, and table 25OBDG04B sets the code once that O2 reading exceeds 29 percent, clearly more than the roughly 21 percent of fresh air, in 100 of 200 samples under the same enable conditions as the low check; Type B, MIL after two trips. Such a figure hints at a signal fault in the sensor or its wiring rather than real exhaust oxygen. The harness bulletins PIT5751C and 21-NA-149 for 2020-21 GM models with the 3.0L LM2 list P2C64 as well. P2C62 is the open circuit, P23AF the NOx circuit high code of the same sensor.
P2C64 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2C64
- MIL on after two trips
- Further NOx sensor or aftertreatment codes stored
Common causes of P2C64
- Most likelyThird exhaust sensor (on GM diesels NOx sensor 3) delivering an implausibly high O2 value
- PossibleEngine harness chafed or shorted (GM 3.0L LM2, PIT5751C)
- Less likelyMoisture or corrosion in the sensor connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor b1s3Nox sensorOxygen sensor wiringECM
What each part of P2C64 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| C | Area: hybrid propulsion. |
| 64 | The exact fault in that area. |
What to do next
- Note P2C64 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2C64
What does P2C64 mean?
P2C64 means "O2 Sensor Pumping Current Trim Circuit High Bank 1 Sensor 3". P2C64 is the high-side partner of P2C63: the oxygen reading attributed to sensor 3 of bank 1 climbs above what the probe can physically deliver. It is a generic code, so it means the same on every make.
Is it safe to drive with P2C64?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2C64 fail an emissions test?
Yes, it can. P2C64 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2C64 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P2C64 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.