P0C9C code meaning
14 Volt Power Module Current Sensor B Circuit
Powertrain system Generic code P0Cxx codes Check engine light
What P0C9C means
P0C9C flags an electrical problem, not further classified, with current sensor B of the 14 volt power module, the DC/DC converter that supplies the 12 V network from the high-voltage battery; GM calls it the accessory power module (APM). In GM's 2013 eAssist table sensor B is the APM output current sensor, while sensor A (P0A86 to P0A8A) measures the input side. No manufacturer documents P0C9C publicly; GM uses only the low and high codes P0C9E and P0C9F plus the A/B correlation code P0CC5. CARB rule (e)(15.3.1) calls for continuous range and continuity monitoring of such inputs. With no trustworthy output current the converter may be derated, and the 12 V battery can slowly discharge. The sensor normally sits inside the module.
P0C9C at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor1 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P0C9C
- Warning lamp, sometimes a charging-system message
- 12 V battery running low over time
Common causes of P0C9C
- Most likelyCurrent sensor B inside the power module failed
- PossiblePoor contact at the power module signal connector
- Less likelyControl software of the power module or hybrid controller
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Pm14v current sensor bWiring harnessDcdc converter
What each part of P0C9C means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C | Area: hybrid propulsion. |
| 9C | The exact fault in that area. |
What to do next
- Note P0C9C 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 P0C9C
What does P0C9C mean?
P0C9C means "14 Volt Power Module Current Sensor B Circuit". P0C9C flags an electrical problem, not further classified, with current sensor B of the 14 volt power module, the DC/DC converter that supplies the 12 V network from the high-voltage battery; GM calls it the accessory power module (APM). It is a generic code, so it means the same on every make.
Is it safe to drive with P0C9C?
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 P0C9C fail an emissions test?
Yes, it can. P0C9C 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 P0C9C to fix?
Difficulty: workshop only. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P0C9C clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.