P01EF

Engine Coolant Heater B Control Circuit Performance

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–167 (est.)

Symptoms

Extended engine warm-up time
Unstable engine operation at idle
Check Engine Light Illuminates

Causes

Coolant Heater B Malfunction
Open or short circuit in wiring harness
Relay or fuse problems
Engine control unit (ECU) malfunction

How to Fix

Check the integrity of the wiring harness and connections
Check fuses and relays associated with the heater
Test coolant heater B for resistance
If necessary, replace the heater or repair the wiring
Reset the error and check if it returns

Related codes

P01EE P01F0 P0128