P0CE9: Hybrid/EV Electronics Coolant Pump A Control Circuit/Open
What to do
As P0C31 — check the electronics coolant level first; it is a separate reservoir from the engine's and easy to overlook, and if there has been recent coolant work, have the circuit properly bled. Expect slower charging while it is unfixed.
What this code means
The control circuit for electronics coolant pump A is open or faulty.
The electronics cooling circuit and its performance codes are at P0C31 and P0C73; this is pump A's control circuit specifically, and pump B's equivalent is at P0B38.
The thing to carry from all of them is when these pumps run: not only while driving, but during charging and for a period after shutdown, because the charger and converter do their hardest work while the car looks completely inert. So the commonest real symptom of a failed electronics pump is charging that has quietly become slower, and nobody connects the two.
Likely causes
Start here
- Faulty inverter coolant pump · moderate
- Air trapped in the inverter cooling circuit · moderate
- Low inverter coolant level · easy
Less common
- Corroded or loose connector · easy
- Open circuit in pump wiring · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P0CE9.