Diagnostic Routine K

Diagnostic Routine K

Diagnostic Overview

The Audio Control Module (ACM) Does Not Respond To The Scan Tool

Refer to Wiring Diagram Set 14 for schematic and connector information Electrical Diagrams.

Refer to Wiring Diagram Set 130 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

The ACM (Audio Control Module) communicates with the scan tool through the MS-CAN (Medium Speed Controller Area Network). The IPC (Instrument Panel Cluster) is used as the gateway module.

Visual Inspection and Diagnostic Pre-checks

Verify BCM (Body Control Module) fuse 79 (15A) is OK.

Pinpoint Test

1. CHECK THE I-CAN (Infotainment Controller Area Network) TERMINATION RESISTANCE

1. Ignition OFF.

2. Measure:





Is the resistance between 54 and 66 ohms?






2. CHECK THE I-CAN (Infotainment Controller Area Network) TERMINATION RESISTANCE WITH THE ACM (Audio Control Module) DISCONNECTED

1. Disconnect: ACM (Audio Control Module) C240A.

2. Measure:





Is the resistance between 108 and 132 ohms?






3. CHECK THE ACM (Audio Control Module) VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: ACM (Audio Control Module) C240A.

3. Ignition ON.

4. Measure:





Are the voltages greater than 11 volts?






4. CHECK THE ACM (Audio Control Module) GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Measure:





Is the resistance less than 3 ohms?






5. CHECK THE I-CAN (Infotainment Controller Area Network) CIRCUITS BETWEEN THE ACM (Audio Control Module) AND THE IPC (Instrument Panel Cluster) FOR AN OPEN

1. Disconnect: IPC (Instrument Panel Cluster).

2. Measure:





Are the resistances less than 3 ohms?






6. CHECK THE I-CAN (Infotainment Controller Area Network) CIRCUITS FOR A SHORT TO POWER

1. Connect: ACM (Audio Control Module) C240A.

2. Ignition ON.

3. Measure:





Is the voltage greater than 6 volts on either circuit?






7. CHECK THE I-CAN (Infotainment Controller Area Network) CIRCUITS FOR A SHORT TO GROUND

1. Ignition OFF.

2. Measure:





Are the resistances greater than 10,000 ohms?






8. CHECK FOR CORRECT ACM (Audio Control Module) OPERATION

1. Ignition OFF.

2. Disconnect and inspect all the ACM (Audio Control Module) connectors.

3. Repair:

- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary

4. Reconnect the ACM (Audio Control Module) connectors. Make sure they seat and latch correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?