Pinpoint Test N: Poor Quality/Distorted/No Sound From All Speakers

Information and Entertainment System

Pinpoint Test N: Poor Quality/Distorted/No Sound From All Speakers

NOTE: In Normal Operation, the terms Audio Front Control Module (ACM) and in-dash computer are synonymous.

Normal Operation

When the ignition is in the START position, voltage is supplied to the Audio Front Control Module (ACM) through the start sense circuit. When the ACM (Audio Front Control Module) receives this voltage, it mutes the speaker output to prevent popping in the speakers as a result of voltage spikes during engine cranking, However, if there is a short to voltage on this circuit, the ACM (Audio Front Control Module) continuously mutes the audio output, resulting in no sound from all speakers.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- ACM (Audio Front Control Module) (vehicles without Ford Work Solutions(TM))

- In-dash computer (vehicles with Ford Work Solutions(TM))

PINPOINT TEST N : POOR QUALITY/DISTORTED/NO SOUND FROM ALL SPEAKERS

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

N1 CHECK THE START SENSE CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Disconnect: ACM (Audio Front Control Module) C240A (In-Dash Computer C2408A).

- Ignition ON.

- Measure the voltage between the ACM (Audio Front Control Module) (in-dash computer) C240A-15 (C2408A-15), circuit CDC38 (WH/VT), harness side and ground.





Is any voltage present?

Yes
REPAIR the circuit. TEST the system for normal operation.

No
GO to N2.

N2 CHECK FOR CORRECT ACM (Audio Front Control Module) (IN-DASH COMPUTER) OPERATION

- Ignition OFF.

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

- Check for:
- corrosion

- damaged pins

- pushed-out pins


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

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

Is the concern still present?

Yes
INSTALL a new ACM (Audio Front Control Module) (in-dash computer). REFER to Audio Control Module (ACM) or In-Dash Computer . 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.