U02C1 code meaning
Lost Communication With Hybrid/EV Electronics Coolant Pump C
Network system Generic code U02xx codes Check engine light
What U02C1 means
U02C1 concerns the third networked pump of the electronics cooling loop, pump C, which has gone quiet on its data line. Vehicles with three such pumps assign them to different branches, and which branch pump C serves is the maker's choice; no manufacturer documents U02C1 publicly. Stellantis' 2024-2025 EV platform shows why the pumps must be kept apart: the units look and fit alike, yet each carries its own part number and software so the EVCU can address it on its own LIN bus, and only the position on the bracket and a symbol tell them apart (STAR S2508000056). Bosch markets electric pumps of this class for cooling power electronics in hybrid and electric cars. Under CARB 1968.2 a mute digital input needs its own fault code. If its branch overheats, power is reduced.
U02C1 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of U02C1
- Warning for the electric drive or charging system
- Reduced power or charging rate under load or heat
- Cooling fans running hard
Common causes of U02C1
- Most likelyPump connector or LIN wire faulty
- PossibleLook-alike pumps swapped between positions during service
- PossiblePump electronics or motor failed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv electronics coolant pump cVehicle bus wiring
What each part of U02C1 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C1 | The exact fault in that area. |
What to do next
- Note U02C1 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 U02C1
What does U02C1 mean?
U02C1 means "Lost Communication With Hybrid/EV Electronics Coolant Pump C". U02C1 concerns the third networked pump of the electronics cooling loop, pump C, which has gone quiet on its data line. It is a generic code, so it means the same on every make.
Is it safe to drive with U02C1?
Drive gently and only to a workshop. With U02C1 the car can go into limp mode (reduced power) to protect itself.
Will U02C1 fail an emissions test?
Yes, it can. U02C1 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 U02C1 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U02C1 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.