Possible causes

– Can ‘C’ Bus Circuit harness is open or shorted
– Faulty Anti-Lock Brake System (ABS) harness is open or shorted
– Faulty Powertrain Control Module (PCM)

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

U1120 DODGE Description

The Powertrain Control Module (PCM) doesn’t receive a wheel distance message from the Anti-lock brake Module or FCM (NON-ABS) over the CAN C bus. One trip fault.