U0636

Lost Communication With Hybrid/EV Battery Pack Coolant Control Valve A

Severity

🔴 High

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$28–167 (est.)

Symptoms

Hybrid system warning light comes on
Hybrid system power reduction
High voltage battery overheating
Speed limit
Unstable operation of the cooling system

Causes

Open or short circuit in valve control circuit
Cooling solenoid valve malfunction
Damage to wiring harness or connectors
Problems with the car's CAN bus
Control unit software error

How to Fix

Check the integrity of the valve circuit wiring and connectors
Test solenoid valve resistance
Scan the CAN bus for communication errors
Replace faulty cooling valve if necessary
Update control unit software

Related codes

U0635 U0637 U0638