Pinpoint Test AX: DTC U0249 Or DTC U0249:00
Information and Entertainment System
Pinpoint Tests
Pinpoint Test AX: DTC U0249 Or DTC U0249:00
Normal Operation
Several audio system modules receive network messages from the audio Rear Control Unit (RCU) module via the Medium Speed Controller Area Network (MS-CAN).
As more than one module receives each of these messages, all modules receiving a particular message should exhibit a symptom if the message is missing.
- DTC U0249 (Lost Communication With Entertainment Control Module - Rear "B" (RCU)) - set by the non-navigation Audio Control Module (ACM) and the Satellite Digital Audio Receiver System (SDARS) module when network messages are missing from the audio RCU module for greater than 5 seconds with the ignition in RUN.
- DTC U0249:00 (Lost Communication With Entertainment Control Module-Rear "B": No Sub Type Information) - set by the navigation ACM and the Accessory Protocol Interface Module (APIM) when network messages are missing from the audio RCU module for greater than 5 seconds with the ignition in RUN.
This pinpoint test is intended to diagnose the following:
- Communication network concern
- Audio system concern
- Audio RCU module
PINPOINT TEST AX: DTC U0249 OR DTC U0249:00
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AX1 CHECK FOR LOST COMMUNICATION DTCs
- Ignition ON.
- Clear continuous DTCs from all modules.
- Ignition OFF.
- Ignition ON.
- Wait at least 10 seconds.
- Retrieve all continuous DTCs from all modules.
- Is DTC U0249 or DTC U0249:00 set in any audio system module?
Yes
GO to AX2.
No
The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.
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AX2 CHECK FOR BATTERY VOLTAGE OUT-OF-RANGE DTCs
- Carry out the self-test for the following modules:
- ACM
- Audio RCU module
- SDARS module (if equipped)
- APIM (if equipped)
- Is DTC B1317, B1318, U3003:16, or U3003:17 recorded in any module?
Yes
GO to DTC Charts. Diagnostic Trouble Code Tests and Associated Procedures
No
GO to AX3.
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AX3 CHECK FOR DTC U0249 OR DTC U0249:00 SET IN MULTIPLE MODULES
- Review the recorded results from the self-test.
- Is DTC U0249 or DTC U0249:00 set in more than one audio system module?
Yes
GO to AX4.
No
If there is an observable symptom, GO to Symptom Chart - General Audio System to diagnose the observed symptom. Symptom Chart - General Audio System
If there is no observable symptom, DISREGARD the DTC.
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AX4 CHECK FOR CORRECT AUDIO RCU MODULE OPERATION
- Ignition OFF.
- Disconnect the audio RCU module connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the audio RCU module connector and make sure it seats correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes
INSTALL a new audio RCU module. REFER to Audio Rear Control Unit (RCU) Module Audio Rear Control Unit (RCU) Module. CLEAR all continuous DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR all continuous DTCs.
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