U0646

Lost Communication With Motor Electronics Coolant Pump A

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$167–500 (est.)

Symptoms

Engine overheating
Reduced engine power
Check Engine Light Is On
Unstable operation of the cooling system
Coolant pump noise

Causes

Open or short circuit in wiring harness
Electronic coolant pump malfunction
Problems with connection connectors
Malfunction of the engine control unit (ECU)
Poor pump grounding

How to Fix

Check the integrity of the wiring harness to the pump
Check the pump connection connectors
Check fuses and pump relays
Diagnose the coolant pump
If necessary, replace the electronic pump

Related codes

U0647 U0645 P2610