U301A

Control Module Wake-up Circuit A/Open

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$6–56 (est.)

Symptoms

The car won't start
Intermittent problems starting the engine
The Check Engine light is on on the dashboard
Lost connection with diagnostic equipment
Failure of individual vehicle systems

Causes

Broken or damaged wires in the wake-up circuit
Oxidized or bad contacts in connectors
Faulty wake-up relay or fuse
Problems with control unit (module) A
Short circuit in the electrical circuit

How to Fix

Check the integrity of the fuses and relays of the wake-up circuit
Inspect the wiring harness for damage or breaks.
Check and clean the contacts in the wake-up circuit connectors
Test control unit (module) A
Check the resistance and continuity of the wake-up circuit

Related codes

U301B U300B U300A