P0E12

Hybrid/EV Battery Pack Coolant Heater A Control Circuit/Open

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–278 (est.)

Symptoms

Hybrid system power reduction
Increased fuel consumption (for hybrids)
Malfunction warning on the dashboard
Reduced battery efficiency in cold weather
System transition to emergency mode

Causes

Broken wires in the heater control circuit
Faulty heater circuit relay or fuse
Damage to the heating element itself
Problems with the battery management module
Corrosion or poor contact in connectors

How to Fix

Check heater circuit fuses and relays
Inspect the wiring harness for damage
Check the resistance of the heating element
Diagnose the battery control module
Check the contacts in the circuit connectors

Related codes

P0E10 P0E11 P0E13