U063CLost Communication With Coolant Bypass Valve Actuator B
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- U063C is the counterpart for the second networked coolant bypass actuator, B. Stellantis lists it for the 3.0-litre Hurricane straight six: bulletin 18-071-26 (2025 Ram 1500) and bulletins 18-082-26 and 18-083-26 (2025 Jeep Wagoneer and Grand Wagoneer) name U063C next to the circuit and performance codes P0E7C to P0E7F of the same valve. In these cases the root cause is powertrain control module software, and the repair is a PCM check and reflash of about 0.2 hours; no hardware has to be replaced. The MIL is lit. Where no such update applies, a lost bus link to actuator B still points to wiring, connector or the actuator. A failed valve can disturb warm-up, cabin heat or coolant temperature control.
- What you may notice
- Malfunction indicator lamp on
- Codes P0E7C to P0E7F for bypass valve B stored at the same time
- Irregular warm-up or weak cabin heat
- Likely causes
- LikelyPowertrain control module software (Stellantis 18-071-26, 18-082-26, 18-083-26)
- PossibleBus, supply or ground wire to actuator B damaged
- PossibleLoose or corroded actuator B connector
- RareActuator B electronics failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €30 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.