OBD-II code · Network
U0637 Lost Communication With Hybrid/EV Battery Pack Coolant Control Valve B
The vehicle bus reports loss of communication with smart HV battery pack coolant control valve B. Coolant routing for the battery cooling loop cannot be commanded.
Is it safe to drive with U0637?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyBus wiring open or shorted
- PossibleModule without power or ground
- PossibleModule 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
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Hv Battery Coolant Valve B, Vehicle Bus Wiring
Related codes
- U0636Lost Communication With Hybrid/EV Battery Pack Coolant Control Valve A
- U0634Lost Communication With Hybrid/EV Battery Pack Coolant Temperature Sensor A
- U0635Lost Communication With Hybrid/EV Battery Pack Coolant Temperature Sensor B
- U0638Lost Communication With Hybrid/EV Electronics Coolant Temperature Sensor A
- U0639Lost Communication With Hybrid/EV Electronics Coolant Temperature Sensor B
- U063ALost Communication With Hybrid/EV Electronics Coolant Temperature Sensor C
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.