Pinpoint Test D: Loud Popping Sound When Cycling The Ignition Switch

Information and Entertainment System

Pinpoint Tests

Pinpoint Test D: Loud Popping Sound When Cycling The Ignition Switch

Refer to Wiring Diagram Set 130, Audio System for schematic and connector information. Diagrams By Number

Normal Operation

Voltage is sent through the start input circuit to the audio unit with the key in START. Upon receiving this signal, the audio unit mutes all speaker outputs to eliminate the possibility of speaker pops during engine cranking.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- Audio unit

PINPOINT TEST D: LOUD POPPING SOUND WHEN CYCLING THE IGNITION SWITCH

NOTICE: For the CD6 audio unit, the audio unit must be placed in shipment mode before removal. Refer to Audio Unit Shipment Mode. Failure to follow this instruction may result in damage to the audio unit. Audio Unit Shipment Mode

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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D1 CHECK THE START SENSE CIRCUIT VOLTAGE

- Ignition OFF.
- Disconnect: Audio Unit C290a.
- Disconnect: Starter Relay C1017.
- Start the engine.
- Measure the voltage between the audio unit C290a-3, circuit CBP22 (GN/OG), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
INSTALL a new audio unit. REFER to Audio Unit Audio Unit. TEST the system for normal operation.

No
VERIFY the Smart Junction Box (SJB) fuse 22 (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. Diagrams By Number

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