U009A

Vehicle Communication Bus H (-) shorted to Bus H (+)

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$6–56 (est.)

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

U0100 U0121 U0155