A Loud Popping Sound Is Heard When Cycling The Ignition
Refer to Wiring Diagrams Cell 20 for schematic and connector information.
Normal Operation and Fault Conditions
The ACM receives voltage on a start signal circuit when the ignition is in the START position, and mutes the audio signal output. This prevents voltage spikes from producing popping noises through the speakers. An open on this circuit between splice CS101 and the ACM could cause voltage spikes to produce popping noises through the speakers.
Possible Sources
Wiring, terminals, or connectors ACM
PINPOINT TEST D : A LOUD POPPING SOUND IS HEARD WHEN CYCLING THE IGNITION
D1 CHECK THE START SENSE CIRCUIT FOR AN OPEN
Ignition OFF. Disconnect: ACM C240A. Remove: BJB Starter Relay. Disconnect:
PCM C1551B for vehicles with the 2.3L EcoBoost (201kW/273PS). PCM C1381B for vehicles with the 3.7L Duratec (227kW/301PS). PCM C175B for vehicles with the 5.0L 32V Ti-VCT. PCM C175B for vehicles with the 5.2L.
Click to display connectors
For vehicles with the 2.3L EcoBoost (201kW/273PS), measure:
Positive Lead | Measurement / Action | Negative Lead |
|---|---|---|
C240A-3 | BJB Starter Relay Socket 1 |
Click to display connectors
Positive Lead | Measurement / Action | Negative Lead |
|---|---|---|
C240A-3 | C1551B-62 |
Click to display connectors
For vehicles with the 3.7L Duratec (227kW/301PS), measure:
Positive Lead | Measurement / Action | Negative Lead |
|---|---|---|
C240A-3 | BJB Starter Relay Socket 1 |
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.