Pinpoint Test J : The Audio Control Module (ACM) Does Not Respond To The Diagnostic Scan Tool
WARNING: This page is about a different car, the 2019 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
- Refer to Module Communications Network
for schematic and connector information. Refer to Audio System/Navigation - Without SYNC
for schematic and connector information. Refer to Audio System/Navigation - SYNC
for schematic and connector information.
Normal Operation and Fault Conditions
The ACM communicates with the diagnostic scan tool through the HS-CAN3.
Possible Sources
- Fuse
- Wiring, terminals and connector
- ACM
Visual Inspection and Pre-checks
- Verify BCM fuse 33 (20A) is OK.
- J1 CHECK THE ACM (AUDIO FRONT CONTROL MODULE) VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: ACM C240A.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C240A-1 Ground
Is the voltage greater than 11 volts?
Yes GO to J2 No VERIFY the BCM fuse 33 (20A) is OK. If OK, REPAIR the circuit. If not OK, REFER to OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short. - J2 CHECK THE ACM (AUDIO FRONT CONTROL MODULE) GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure:
Positive Lead Measurement / Action Negative Lead C240A-13 Ground
Is the resistance less than 3 ohms?
Yes GO to J3 No REPAIR the circuit. - J3 CHECK THE HS-CAN3 (HIGH-SPEED CONTROLLER AREA NETWORK 3) CIRCUITS BETWEEN THE ACM (AUDIO FRONT CONTROL MODULE) AND THE GWM (GATEWAY MODULE A) FOR AN OPEN
- Disconnect GWM C2431.
Are the resistances less than 3 ohms?
Yes GO to J4 No REPAIR the circuit in question. - J4 CHECK FOR CORRECT ACM (AUDIO FRONT CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect all the ACM connectors.
- 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
- Reconnect the ACM connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, General Service Bulletin (GSB), SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new ACM. Refer to the appropriate Information and Entertainment System article for the procedure. No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.