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, Module Communications Network for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information. Diagrams By Number
Normal Operation and Fault Conditions
The ACM (Audio Control Module) communicates with the scan tool through the I-CAN (Infotainment Controller Area Network).
Visual Inspection and Diagnostic Pre-checks
Verify BCM (Body Control Module) fuse 29 (20A) 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 DLC (Data Link Connector) FOR AN OPEN
1. 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 3 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 the ACM (Audio Control Module) connectors.
3. Repair:
- corrosion (replace connector or terminals - clean module pins)
- damaged or bent pins - replace terminals/pins
- pushed-out pins - replace pins as necessary
4. Reconnect the ACM (Audio Control Module) connectors. Make sure they seat and latch correctly.
5. Operate the system and verify the concern is still present.
Is the concern still present?
