Entertainment Systems

PINPOINT TEST 13: DTC U0140

Normal Operation

Several audio system modules receive network messages from the smart junction box (SJB). The following information is included in the message:

- Ignition switch position
- Illumination dimmer control
- Accessory delay status

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 U0140 (Lost Communication With Body Control Module [GEM]) - set by the audio control module (ACM) when network messages are missing from the SJB for greater than 5 seconds with the key in the RUN position.

Possible Causes
- Communication network concern
- Audio system concern
- SJB

Diagnostic Procedure

CAUTION:Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

Step 1-Step 3:

Step 4: