U0618

Lost Communication With Engine Coolant Bypass Valve D

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$28–89 (est.)

Symptoms

Check Engine light comes on
Unstable engine operation when warming up
Engine overheating
Decrease in interior heater efficiency
Incorrect coolant temperature readings

Causes

Open or short circuit in valve circuit
Bypass solenoid valve malfunction
Poor contact in valve connector
Wiring harness damage
Software error in the ECU

How to Fix

Check the integrity of wiring and connectors
Test bypass valve resistance
Check voltage at valve connector
Replace faulty bypass valve
Update ECU firmware if necessary

Related codes

U0615 U0617 U0619