Pinpoint Test 9: The Audio Control Module (ACM) Does Not Respond To The Scan Tool

PINPOINT TEST 9: THE AUDIO CONTROL MODULE (ACM) DOES NOT RESPOND TO THE SCAN TOOL

Normal Operation

The audio control module (ACM) communicates with the scan tool through the medium speed controller area network (MS-CAN). Circuits (GY/O) (MS-CAN +) and (V/O) (MS-CAN -) provide the network connection to the ACM. The ACM shares the MS-CAN with the instrument cluster (IC), HVAC module, smart junction box (SJB), satellite digital audio receiver system (SDARS) module, front controls interface module (FCIM) and front display interface module (FDIM). Voltage for the ACM is provided by circuit (W/R). Ground is provided by circuit (B/GY).

Possible Causes
- Fuse
- Wiring, terminals or connectors
- Audio unit

Diagnostic Procedure

CAUTION:Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE:Failure to disconnect the battery when instructed will result in false resistance readings. See Battery Disconnect.