P2B72

Coolant Heater A Control Circuit/Open

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–56 (est.)

Symptoms

Extended engine warm-up time
Unstable operation at idle
Check Engine light comes on
Reduced engine efficiency in cold weather

Causes

Heater control circuit open
Coolant heater malfunction
Relay or fuse problems
Control module malfunction
Corrosion or poor contact in connectors

How to Fix

Check heater circuit fuse and relay
Inspect connectors and wires for damage
Check heater resistance
Diagnose the control module
Replace coolant heater if necessary

Related codes

P2B73 P2B74 P2B75