DTC U1120: Failure Information On Powertrain Control Module (Related To Engine): Notes
WARNING: This page is about a different car, the 2004 Mitsubishi Galant. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
If DTC U1120 is set in the combination meter, diagnose the CAN main bus line.
CAUTION:
If DTC U1120 has been set, SWS related DTC 021 is also set. After SWS has been diagnosed, don't forget to erase DTC 021.
CAUTION:
The engine control system-related DTC may be set when DTC U1120 is set. (For details refer to INTERSYSTEM AFFILIATED DTC REFERENCE TABLE
.)
Diagnose the engine control system first when the engine control system-related DTC is set.