P2B74

Coolant Heater A Control Circuit High

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–89 (est.)

Symptoms

Malfunction of the coolant heating system
Cold air from the interior heating system at low temperatures
Extended engine warm-up time
The Check Engine light comes on

Causes

Coolant heater malfunction
Open or short circuit in control circuit
Problems with the heater relay
Engine control unit malfunction
Corrosion of contacts or connectors

How to Fix

Checking and testing the coolant heater
Checking the integrity of the heater control circuit
Heater relay diagnostics
Checking contacts and connectors for corrosion
Reflashing or replacing the control unit if necessary

Related codes

P2B73 P2B75 P2B72