U0635

Lost Communication With Hybrid/EV Battery Pack Coolant Temperature Sensor B

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$28–89 (est.)

Symptoms

Check Engine light comes on
Hybrid system power reduction
Incorrect battery temperature readings on the dashboard
Activation of emergency operation
Increased noise of the cooling system

Causes

Open or short circuit in the sensor circuit
Coolant temperature sensor B malfunction
Poor contact in the sensor connector
Wiring harness damage
Hybrid ECU malfunction

How to Fix

Check the integrity of the sensor circuit (open/short circuit)
Check the connectors and contacts of the sensor
Test temperature sensor (resistance/signal)
Replace the faulty sensor if necessary
Check and reflash the ECU if it is suspected of being faulty

Related codes

U0634 U0636 U0637