U301B
Control Module Wake-up Circuit A Low
U301B is an OBD-II diagnostic trouble code meaning: Control Module Wake-up Circuit A Low. Common causes: broken or damaged wires in the wake-up circuit, poor contact in module connectors. Estimated repair cost: $17–89.
Symptoms
- Engine won't start
- Intermittent electronic failures
- Check Engine Light Is On
- The module does not respond during diagnostics
- Random malfunctions in vehicle systems
Causes
- Broken or damaged wires in the wake-up circuit
- Poor contact in module connectors
- Short circuit to ground
- Faulty relay or fuse
- Problems with the control module itself
How to Fix
- Check the integrity of fuses and relays
- Inspect the wiring harness for damage
- Check the quality of contacts in the module connectors
- Diagnose wake-up circuit resistance
- Check the control module itself for faults
Related codes
Error U301B by Vehicle Brand
FAQ
What does the U301B code mean?
U301B is an OBD-II diagnostic trouble code that indicates: Control Module Wake-up Circuit A Low
What causes a U301B error code?
The most common causes of U301B include: Broken or damaged wires in the wake-up circuit; Poor contact in module connectors; Short circuit to ground; Faulty relay or fuse.
How do I fix a U301B diagnostic trouble code?
To fix U301B: Check the integrity of fuses and relays. Inspect the wiring harness for damage. Check the quality of contacts in the module connectors. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U301B?
Do not drive — repair immediately
How much does it cost to fix U301B?
The estimated repair cost for U301B is $17–89. Actual cost depends on your vehicle, location, and labor rates.
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