P0CE9 code meaning
Hybrid/EV Electronics Coolant Pump A Control Circuit/Open
Powertrain system Generic code P0Cxx codes Check engine light
What P0CE9 means
The hybrid controller checks the control line of the electric pump that moves coolant through the power electronics loop, which in GM's Volt and ELR serves the inverter module and the high-voltage charger. GM tables from 2011 to 2016 fail it when the output driver reports an open line or a short to ground or voltage in 16 of 20 samples at 250 ms. The 2019 HPC2 table measures line current instead: below 200 mA or above 3 A while the pump is commanded on, below 120 µA while it is off, for 4 s within a 5 s window. All variants are Type B, two trips. Audi logs P0CE900 on the e-tron and Q8 e-tron in thermal management unit 00C5. P0CEB and P0CEC split the fault into low and high, P0CEA covers pump function. With the pump idle, inverter and charger heat up and power is reduced.
P0CE9 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0CE9
- Malfunction indicator lamp or hybrid/drive system warning on
- Reduced drive power because inverter and charger temperatures rise
- Charging power reduced or charging interrupted
- Pump not audible after switch-on when commanded via scan tool
Common causes of P0CE9
- Most likelyOpen or chafed control wire, or corroded connector at the electronics coolant pump
- PossibleFailed electronics in the pump itself, drawing no current or far too much
- Less likelyCoolant loss from a damaged hose letting the pump run dry (Audi e-tron/Q8 e-tron bulletin)
- Less likelyFaulty output driver in the hybrid or thermal management control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hybrid electronics coolant pump aWiring harnessHybrid control module
What each part of P0CE9 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. |
| E9 | The exact fault in that area. |
What to do next
- Note P0CE9 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 P0CE9
What does P0CE9 mean?
P0CE9 means "Hybrid/EV Electronics Coolant Pump A Control Circuit/Open". The hybrid controller checks the control line of the electric pump that moves coolant through the power electronics loop, which in GM's Volt and ELR serves the inverter module and the high-voltage charger. It is a generic code, so it means the same on every make.
Is it safe to drive with P0CE9?
Drive gently and only to a workshop. With P0CE9 the car can go into limp mode (reduced power) to protect itself.
Will P0CE9 fail an emissions test?
Yes, it can. P0CE9 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 P0CE9 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0CE9 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.