P01EB

Engine Coolant Heater A 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
Reduced cabin heating efficiency
Check Engine Light Illuminates

Causes

Open or short circuit in the control circuit wiring harness
Heater solenoid valve malfunction
Heater control relay problems
Failure of the coolant heater itself
Poor contact in circuit connectors
Engine control unit malfunction

How to Fix

Check the integrity of the heater control circuit wiring harness
Check control circuit fuse and relay
Test heater and solenoid valve resistance
Inspect connectors for corrosion or damage
Check control signals from the ECU using an oscilloscope
If necessary, replace faulty components
Clear error memory and check if code is returned

Related codes

P01EC P0128 P0480