What it means
The vehicle bus reports loss of communication with the hybrid/EV power-electronics coolant pump C. Inverters and DC/DC stages on this loop lose active cooling and may derate.
At a glance
- Usually lights the warning light of the system that lost communication
- The engine or gearbox may go into limp mode
How it works
Hybrid/EV electronics coolant pump C circulates coolant through a power-electronics cooling loop that can include inverters and DC/DC stages. The vehicle network lets controllers command the pump and check its status. This code sets when communication with pump C is lost; the electronics it cools may then overheat or reduce output.
Common causes
Most likely first.
- Bus wiring open or shorted
- Module without power or ground
- Module failed
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all hybrid and EV modules for related pump, cooling, and communication faults, and save freeze-frame data before clearing anything.
- Check live data for pump C communication, commanded operation, and coolant-temperature warnings to determine whether the fault is current.
- With the vehicle off and following its high-voltage safety instructions, inspect pump C's low-voltage connector and harness for looseness, damage, or corrosion.
- Have pump C's power and ground circuits checked under the manufacturer's procedure, because a supply fault can take the pump offline.
- Test the network wiring to pump C for opens, shorts, or poor connections; consider pump-module failure only after wiring and supplies pass.
Common fixes
- Secure the pump C connector or repair visible low-voltage harness damage.
- Repair an open, short, or poor connection in the pump C network wiring.
- Restore a failed power or ground connection to pump C.
- Replace the pump C assembly if its network and supply circuits are sound but it does not communicate.
Can I keep driving?
Do not continue driving if a hybrid or EV cooling warning appears, power is reduced, or the vehicle reports an electronics temperature fault; stop safely and arrange recovery. Loss of pump C can overheat power electronics and lead to shutdown or costly damage.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.