Pinpoint Test R: DTC U0255:00 Or DTC U0257:00

Information and Entertainment System

Pinpoint Test R: DTC U0255:00 Or DTC U0257:00

- DTC U0255:00 (Lost Communication With Front Display Interface Module: No Sub Type Information) - set by the Accessory Protocol Interface Module (APIM) when network messages are missing from the Front Control/Display Interface Module (FCDIM) for greater than 5 seconds with the ignition in RUN.
- DTC U0257:00 (Lost Communication With Front Controls/Display Interface Module: No Sub Type Information) - set by the Audio Control Module (ACM) when network messages are missing from the FCDIM for greater than 5 seconds with the ignition in RUN.

This pinpoint test is intended to diagnose the following:

- Communication network concern
- ACM
- APIM
- FCDIM

PINPOINT TEST R: DTC U0255:00 OR DTC U0257:00

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

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R1 CHECK FOR LOST COMMUNICATION 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.

- Ignition ON.
- Clear the ACM and APIM DTCs.
- Ignition OFF.
- Ignition ON.
- Wait at least 10 seconds.
- Repeat the ACM and APIM self-test.
- Is DTC U0255:00 or DTC U0257:00 still present?

Yes
GO to R2.

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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R2 VERIFY THE CUSTOMER CONCERN

- Operate the audio system in various modes (radio tuner, SYNC(R), etc.).
- Verify there is an observable symptom present.
- Is an observable symptom present?

Yes
GO to R3.

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

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R3 CHECK THE COMMUNICATION NETWORK

- Carry out the network test using the scan tool.
- Does the FCDIM pass the network test?

Yes
GO to R4.

No
REFER to The FCDIM Does Not Respond To The Scan Tool in Module Communications Network Testing and Inspection.

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R4 CHECK FOR BATTERY VOLTAGE OUT-OF-RANGE DTCs

- Carry out the self-test for the following modules:
- ACM
- APIM
- FCDIM
- Are any low or high voltage DTCs recorded in any module?

Yes
REFER to DTC Charts. [1][2]Diagnostic Trouble Code Descriptions

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

If DTC U0257:00 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 U0255:00 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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