Pinpoint Test E: Loud Popping Sound When Cycling The Ignition
Information and Entertainment System
Pinpoint Tests
Pinpoint Test E: Loud Popping Sound When Cycling The Ignition
Refer to Wiring Diagram Set 130 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Audio System/Navigation for schematic and connector information. Diagrams By Number
Normal Operation
Voltage is sent through the start input circuit CBP28 (GY/VT) to the Audio Control Module (ACM) with the ignition in the START position. Upon receiving this signal, the ACM mutes all speaker outputs to eliminate the possibility of voltage spikes producing a popping noise through the speakers.
For the Audiophile audio system, the ACM disables the subwoofer while the ignition is in the START position by keeping the enable signal below 0.4 volt on circuit SME23 (VT/RD). If there is a short to voltage on circuit SME23 (VT/RD), distortion will be heard in the subwoofer whenever the ACM is powered up, and that should be the primary concern addressed. If the subwoofer has distorted sound, Go To Pinpoint Test D. Pinpoint Test D: The Subwoofer Is Inoperative/Does Not Operate Correctly
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Subwoofer (Audiophile)
- ACM
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.
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E1 CHECK CIRCUIT CBP28 (GY/VT) FOR VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240a.
- Disconnect: Starter Relay.
- Hold the key in the START position.
- Measure the voltage between the ACM C240a-15, circuit CBP28 (GY/VT), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
For the Audiophile audio system, GO to E2.
For all others, INSTALL a new ACM. 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.
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E2 ISOLATE THE SUBWOOFER
- Ignition OFF.
- Connect: ACM C240a.
- Disconnect: Subwoofer C466.
- Cycle the key through all of the ignition switch positions.
- Is a loud popping sound present?
Yes
INSTALL a new ACM. REFER to Audio Control Module (ACM) Audio Control Module (ACM). TEST the system for normal operation.
No
INSTALL a new subwoofer. REFER to Subwoofer Speaker Subwoofer Speaker. TEST the system for normal operation.
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