Pinpoint Test E: Loud Popping Sound When Cycling The Ignition

Information and Entertainment System

Pinpoint Test E: Loud Popping Sound When Cycling The Ignition


Normal Operation

Voltage is sent through the start input circuit to the Audio Front Control Module (ACM) with the ignition in the START position. Upon receiving this signal, the ACM (Audio Front Control Module) mutes all speaker outputs to eliminate the possibility of voltage spikes producing a popping noise through the speakers.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- ACM (Audio Front Control Module)

PINPOINT TEST E : LOUD POPPING SOUND WHEN CYCLING THE IGNITION

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

E1 CHECK THE START SENSE CIRCUIT FOR VOLTAGE

- Ignition OFF.

- Disconnect: ACM (Audio Front Control Module) C240A.

- Disconnect: Starter Relay.

- Hold the key in the START position.

- Measure the voltage between the ACM (Audio Front Control Module) C240A-15, circuit CBP28 (GY/VT), harness side and ground.





Is the voltage greater than 10 volts?

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

No
VERIFY the Smart Junction Box (SJB) fuse 28 (5A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.