U063A code meaning
Lost Communication With Hybrid/EV Electronics Coolant Temperature Sensor C
Network system Generic code U06xx codes Check engine light
What U063A means
Sensor C is the third digitally connected temperature sensor in the cooling loop for the hybrid or EV power electronics. It is found where a system splits the loop further, for example to give a DC/DC converter or onboard charger its own reading. U063A is stored when its frames stop arriving. No public manufacturer documentation names this code or the location of sensor C. California's OBD II rule lists inverter cooling inputs among the monitored parts, so a hybrid has to flag the loss. If only U063A is present while A and B still answer, a local fault at sensor C or its branch of the harness is far more likely than a bus-wide problem. The analog counterparts are P2B24 to P2B27.
U063A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U063A
- Hybrid or EV warning lamp
- Possible reduction of charging or drive power
Common causes of U063A
- Most likelyOpen or chafed wire in the branch that feeds sensor C only
- PossibleSensor C connector unplugged after service work or corroded
- PossibleSensor C electronics defective
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv electronics coolant temp sensor cVehicle bus wiring
What each part of U063A means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3A | The exact fault in that area. |
What to do next
- Note U063A 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 U063A
What does U063A mean?
U063A means "Lost Communication With Hybrid/EV Electronics Coolant Temperature Sensor C". Sensor C is the third digitally connected temperature sensor in the cooling loop for the hybrid or EV power electronics. It is a generic code, so it means the same on every make.
Is it safe to drive with U063A?
Drive gently and only to a workshop. With U063A the car can go into limp mode (reduced power) to protect itself.
Will U063A fail an emissions test?
Yes, it can. U063A 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 U063A to fix?
Difficulty: hard. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will U063A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.