U009A
Vehicle Communication Bus H (-) shorted to Bus H (+)
U009A is an OBD-II diagnostic trouble code meaning: Vehicle Communication Bus H (-) shorted to Bus H (+). Common causes: damage to the can bus wiring harness, short circuit in one of the ecus. Estimated repair cost: $6–56.
Symptoms
- Instruments on the panel do not work or do not work correctly
- The engine runs rough or stalls
- Check Engine light comes on
- There is no connection with diagnostic equipment
- Certain car systems do not work (ABS, ESP, etc.)
Causes
- Damage to the CAN bus wiring harness
- Short circuit in one of the ECUs
- Corrosion or oxidation of connector contacts
- Mechanical damage to wiring
- Malfunction of CAN bus terminators
How to Fix
- Check the integrity of the CAN bus wiring harness
- Check the resistance between lines CAN-H+ and CAN-H-
- Inspect connectors and contacts for corrosion
- Disable the modules one by one to find the faulty ECU
- Check the serviceability of the CAN bus terminators
Related codes
Error U009A by Vehicle Brand
FAQ
What does the U009A code mean?
U009A is an OBD-II diagnostic trouble code that indicates: Vehicle Communication Bus H (-) shorted to Bus H (+)
What causes a U009A error code?
The most common causes of U009A include: Damage to the CAN bus wiring harness; Short circuit in one of the ECUs; Corrosion or oxidation of connector contacts; Mechanical damage to wiring.
How do I fix a U009A diagnostic trouble code?
To fix U009A: Check the integrity of the CAN bus wiring harness. Check the resistance between lines CAN-H+ and CAN-H-. Inspect connectors and contacts for corrosion. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U009A?
Do not drive — repair immediately
How much does it cost to fix U009A?
The estimated repair cost for U009A is $6–56. Actual cost depends on your vehicle, location, and labor rates.
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