Pinpoint Test AT: DTC U0256:00

Information and Entertainment System

Pinpoint Test AT: DTC U0256:00

Normal Operation
- DTC U0256:00 (Lost Communication With Front Controls Interface Module: No Sub Type Information) - set by the Audio Control Module (ACM) or Accessory Protocol Interface Module (APIM) when network messages are missing from the Front Controls Interface Module (FCIM) over the 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
- FCIM
- APIM



PINPOINT TEST AT: DTC U0256:00

NOTE: Disregard the pinpoint test steps for the (id=21)APIM if the concern is on a vehicle without the SYNC system.

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AT1 CHECK THE ACM AND APIM 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 may not have been carried out.

- Clear the ACM and APIM DTCs.
- Ignition OFF.
- Ignition ON.
- Wait at least 10 seconds.
- Repeat the ACM and APIM self-tests.
- Is DTC U0256:00 still present?

Yes
GO to AT2.

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

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AT2 VERIFY THE CUSTOMER CONCERN


- Ignition ON.
- Verify that there is an observable symptom present.
- Is an observable symptom present?

Yes
GO to AT3.

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 wiring between the FCIM and the module in question for an intermittent fault.

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AT3 CHECK THE COMMUNICATION NETWORK


- Ignition ON.
- Carry out the network test using the scan tool.
- Does the FCIM pass the network test?

Yes
GO to AT4.

No
REFER to Information Bus.

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AT4 CHECK FOR BATTERY VOLTAGE OUT-OF-RANGE DTCs


- Carry out the self-test for the following modules:
- ACM
- APIM
- FCIM
- Is DTC B1316, B1317, U3003:16 or U3003:17 recorded in any module?

Yes
REFER to DTC Charts. Diagnostic Trouble Code Tests and Associated Procedures

No
INSTALL a new FCIM. REFER to Front Controls Interface Module (FCIM) - Without Navigation Front Controls Interface Module (FCIM) - Without Navigation or Front Controls Interface Module (FCIM) - With Navigation Front Controls Interface Module (FCIM) - With Navigation. CLEAR the ACM and APIM DTCs. REPEAT the ACM and APIM self-tests.

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

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

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