U0256

Information and Entertainment System

Pinpoint Test AF: DTC U0256:00

Normal Operation

- DTC U0256:00 (Lost Communication With Front Controls Interface Module: No Sub Type Information)- set by the Audio Front Control Module (ACM) or the Accessory Protocol Interface Module (APIM) when network messages are missing from the Front Controls Interface Module (FCIM) over the Medium Speed Controller Area Network (MS-CAN) for greater than 5 seconds with the ignition in the RUN position.

This pinpoint test is intended to diagnose the following:

- Communication network concern

- ACM (Audio Front Control Module)

- FCIM (Front Controls Interface Module)

- APIM (Accessory Protocol Interface Module)

PINPOINT TEST AF : DTC U0256:00

NOTE: Disregard the pinpoint test steps for the APIM (Accessory Protocol Interface Module) if the concern is on a vehicle without the SYNC system.

AF1 CHECK THE ACM (Audio Front Control Module) AND FDIM (Front Display Interface Module) DTCs

NOTE: If new modules were installed prior to the DTC being set, the module configuration may be incorrectly set during Programmable Module Installation (PMI) or the PMI (Programmable Module Installation) may not have been carried out.

- Clear the ACM (Audio Front Control Module) and APIM (Accessory Protocol Interface Module) DTCs.

- Ignition OFF.

- Ignition ON.

- Wait at least 10 seconds.

- Repeat the ACM (Audio Front Control Module) and APIM (Accessory Protocol Interface Module) self-tests.

Is DTC U0256:00 still present?

Yes
GO to AF2.

No
The system is operating correctly at this time. The DTC may have been set due to an intermittent fault in the network wiring.

AF2 VERIFY THE CUSTOMER CONCERN

- Ignition ON.

- Verify that there is an observable symptom present.

Is an observable symptom present?

Yes
GO to AF3.

No
The system is operating correctly at this time. The DTC may have been set due to an intermittent fault in the network wiring. CHECK the MS-CAN (Medium Speed Controller Area Network) wiring between the FCIM (Front Controls Interface Module) and the module in question for a fault.

AF3 CHECK THE COMMUNICATION NETWORK

- Ignition ON.

- Carry out the network test using the scan tool.

Does the FCIM (Front Controls Interface Module) pass the network test?

Yes
GO to AF4.

No
REFER to Information Bus.

AF4 CHECK FOR BATTERY VOLTAGE OUT-OF-RANGE DTCs

- Carry out the self-test for the following modules:
- ACM (Audio Front Control Module)

- APIM (Accessory Protocol Interface Module)

- FCIM (Front Controls Interface Module)

Is DTC U3003:16 or DTC U3003:17 recorded in any module?

Yes
REFER to DTC Charts Accessories and Optional Equipment.

No
INSTALL a new FCIM (Front Controls Interface Module). REFER to Front Controls Interface Module (FCIM) . CLEAR the ACM (Audio Front Control Module) and APIM (Accessory Protocol Interface Module) DTCs. REPEAT the ACM (Audio Front Control Module) and APIM (Accessory Protocol Interface Module) self-tests.

If U0256:00 is still present in the ACM (Audio Front Control Module) , INSTALL a new ACM (Audio Front Control Module). REFER to Audio Control Module (ACM) . TEST the system for normal operation.

If DTC U0256:00 is still present in the APIM (Accessory Protocol Interface Module) , INSTALL a new APIM (Accessory Protocol Interface Module). REFER to Accessory Protocol Interface Module (APIM) . TEST the system for normal operation.