U0009

High Speed CAN Communication Bus (-) shorted to Bus (+)

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$6–56 (est.)

Symptoms

Unstable engine operation
Failure of individual vehicle systems
The Check Engine light comes on
Problems with data transfer between modules

Causes

Damage to the CAN bus wiring harness
Short circuit in one of the connected modules
Mechanical damage to wiring
Corrosion of contacts in connectors

How to Fix

Visual inspection of the CAN bus wiring harness
Checking wiring integrity with a multimeter
Disabling modules one by one to find the faulty one
Repair or replacement of damaged wires

Related codes

U0010 U0011 U0121