Pinpoint Test N: DTC U0140 or DTC U0140:00
Information and Entertainment System
Pinpoint Tests
Pinpoint Test N: DTC U0140 Or DTC U0140:00
Normal Operation
The Audio Control Module (ACM) and Accessory Protocol Interface Module (APIM) (V2) receive the following signals from the Smart Junction Box (SJB) via the Medium Speed Controller Area Network (MS-CAN):
- Ignition switch position
- Illumination
- Delayed accessory enable
Rather than use a battery feed through the ignition switch, the ignition switch position signal is used to "wake up" the audio system modules. If the SJB is not broadcasting the ignition switch position signal, none of the audio system modules can power-up, resulting in the audio system being completely inoperative.
The illumination signal is sent to multiple modules, including the Front Controls Interface Module (FCIM) and the Front Display Interface Module (FDIM). If the SJB is not broadcasting the illumination signal, the FDIM and FCIM default to full nighttime brightness.
The delayed accessory function allows the audio system to be operated for a pre-determined amount of time after the key has been turned to OFF and a front door has not been opened. If the delayed accessory enable message is missing, the audio system defaults to the ignition switch position signal (delayed accessory disabled).
- DTC U0140 (Lost Communication With Body Control Module [GEM]) - set by the ACM when it is missing messages from the SJB for greater than 5 seconds.
- DTC U0140:00 (Lost Communication With Body Control Module: No Sub Type Information) - set by the APIM when it is missing messages from the SJB for greater than 5 seconds.
This pinpoint test is intended to diagnose the following:
- Communication network concern
- SJB
- ACM
PINPOINT TEST N: DTC U0140 OR DTC U0140:00
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N1 CHECK FOR A HARD FAULT
- Ignition ON.
- Using the scan tool, clear the ACM and APIM continuous DTCs.
- Ignition OFF.
- Ignition ON.
- Wait at least 10 seconds.
- Using the scan tool, retrieve the ACM and APIM continuous DTCs.
- Is DTC U0140 or DTC U0140:00 present?
Yes
GO to N2.
No
The concern is not present at this time. DTC U0140 may have set due to a previous low voltage condition or due to an intermittent loss of network communication.
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N2 CHECK COMMUNICATION WITH THE SJB
- Carry out the network test using the scan tool.
- Does the SJB pass the network test?
Yes
For a concern with the ACM, GO to N3.
For a concern with the APIM, GO to N4.
No
REFER to Information Bus to diagnose lost communication with the SJB.
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N3 CHECK FOR CORRECT ACM OPERATION
- Disconnect all the ACM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the ACM connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ACM. REFER to Audio Control Module (ACM) Audio Control Module (ACM). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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N4 CHECK FOR CORRECT APIM OPERATION
- Ignition OFF.
- Disconnect the APIM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pints
- Connect the APIM connector and make sure it seats correctly.
- Wait 2 minutes for the APIM to re-initialize.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new APIM. REFER to Accessory Protocol Interface Module (APIM) Accessory Protocol Interface Module (APIM). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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