U0018

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

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$17–111 (est.)

Symptoms

Unstable engine operation
Failure of safety systems (ABS, ESP)
The Check Engine light comes on
Lost connection with diagnostic equipment
Incorrect operation of the dashboard

Causes

Damage to CAN bus wiring
Corrosion of connectors
Malfunction of one of the CAN network modules
Mechanical damage to the wiring harness
Moisture getting into connectors

How to Fix

Visual inspection of CAN bus wiring and connectors
Checking wiring integrity using a multimeter
Disabling CAN network modules one by one to identify the faulty one
Replacing damaged wires or connectors
Repair or replacement of a faulty module

Related codes

U0019 U0020 U0021