Pinpoint Test F: The ACM (Audio Front Control Module) Is Inoperative/Does Not Operate Correctly (Late Build)

Information and Entertainment System

Pinpoint Test F: The ACM (Audio Front Control Module) Is Inoperative/Does Not Operate Correctly (Late Build)

Refer to Wiring Diagrams Set 14, Module Communications Network for schematic and connector information. Electrical Diagrams

Refer to Wiring Diagrams Set 130, Audio System for schematic and connector information. Electrical Diagrams

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- ACM (Audio Front Control Module)

Normal Operation

The ACM (Audio Front Control Module) sends AC voltage signals to the speakers in order to produce sound. The ACM (Audio Front Control Module) receives voltage at all times in order to retain preset memory.

PINPOINT TEST F : THE ACM (Audio Front Control Module) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY (LATE BUILD)

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

F1 CHECK THE ACM (Audio Front Control Module) VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

- Ignition OFF.

- Disconnect: ACM (Audio Front Control Module) C290A.

- Ignition ON.

- Measure the voltage between the ACM (Audio Front Control Module), harness side and ground.

Positive Meter Lead Negative Meter Lead Circuit C290A-1 Ground 29-MD15 (OG/BK) C290A-2 Ground 75-MD15 (YE/GN)






Is the voltage greater than 10 volts?

Yes
GO to F2.

No
VERIFY that Central Junction Box (CJB) fuses 151 (15A) and 137 (7.5A) are OK. If OK, REPAIR the circuit in question. If not OK, REFER to the Wiring Diagrams to identify the possible cause(s) of the circuit short. Electrical Diagrams

F2 CHECK THE ACM (Audio Front Control Module) GROUND CIRCUITS FOR AN OPEN

- Ignition OFF.

- Measure the voltage between the ACM (Audio Front Control Module), harness side and ground.

Positive Meter Lead Negative Meter Lead Circuit C290A-1 C290A-13 91-MD15 (BK/GN) C290A-1 C290A-4 91-LK34 (BK/GN)






Is the voltage greater than 10 volts?

Yes
GO to F3.

No
REPAIR the circuit in question. TEST the system for normal operation.

F3 CHECK FOR CORRECT ACM (Audio Front Control Module) OPERATION

- Disconnect all the ACM (Audio Front Control Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the ACM (Audio Front Control Module) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new ACM (Audio Front Control Module). REFER to Audio Control Module (ACM) . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.