Pinpoint Test D: The Subwoofer Is Inoperative/Does Not Operate Correctly - Rear Subwoofer
Information and Entertainment System
Pinpoint Tests
Pinpoint Test D: The Subwoofer is Inoperative/Does Not Operate Correctly - Rear Subwoofer
Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information. Diagrams By Number
Normal Operation
The rear subwoofers are powered by a separate subwoofer amplifier for each subwoofer speaker. The enable/clip circuit 174 (GY/BK) carries out 2 functions: to turn on the subwoofer amplifiers, and monitor an overload condition to the subwoofer amplifiers. In the event of an overload, the Audio Control Module (ACM) clips the audio output signal to the subwoofer amplifiers (heard as distortion). The rear subwoofer amplifiers receive voltage through circuit 828 (VT/LB) (right subwoofers) or circuit 830 (PK/YE) (left subwoofers), and ground through circuit 1204 (BK/OG).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Subwoofer amplifier
- Subwoofer
- ACM
PINPOINT TEST D: THE SUBWOOFER IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - REAR SUBWOOFER
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 CIRCUIT 828 (VT/LB) OR 830 (PK/YE) FOR VOLTAGE
- Ignition OFF.
- Disconnect: Suspect Subwoofer Amplifier(s).
- Measure the voltage between the suspect subwoofer amplifier, harness side and ground as follows:
- Is the voltage greater than 10 volts?
Yes
GO to D2.
No
VERIFY the Bussed Electrical Center (BEC) fuse 6 (30A) or fuse 9 (30A) is OK. If OK, REPAIR the circuit in question. 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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D2 CHECK CIRCUIT 1204 (BK/OG) FOR AN OPEN
- Measure the resistance between the suspect subwoofer amplifier, harness side and ground as follows:
- Is the resistance less than 5 ohms?
Yes
GO to D3.
No
REPAIR the circuit in question. TEST the system for normal operation.
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D3 CHECK CIRCUIT 174 (GY/BK) FOR VOLTAGE
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the voltage between the suspect subwoofer speaker, harness side and ground as follows:
- Is the voltage between 3.8 and 6.7 volts?
Yes
GO to D6.
No
GO to D4.
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D4 CHECK CIRCUIT 174 (GY/BK) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290b.
- Ignition ON.
- Measure the voltage between the ACM C290b-8, circuit 174 (GY/BK), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to D5.
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D5 CHECK CIRCUIT 174 (GY/BK) FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect subwoofer amplifier pin 1, circuit 174 (GY/BK), harness side and the ACM C290b-8, circuit 174 (GY/BK), harness side; and between the suspect subwoofer speaker pin 1, circuit 174 (GY/BK), harness side and ground.
- Is the resistance less than 5 ohms between the suspect subwoofer amplifier and the ACM, and greater than 10,000 ohms between the suspect subwoofer amplifier and ground?
Yes
GO to D12.
No
REPAIR the circuit. TEST the system for normal operation.
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D6 CHECK THE AUDIO SIGNALS TO THE SUSPECT SUBWOOFER AMPLIFIER
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage at the suspect subwoofer amplifier, harness side as follows:
- Is a fluctuating AC voltage present?
Yes
GO to D9.
No
GO to D7.
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D7 CHECK CIRCUITS 176 (PK/LG) AND 179 (OG/RD) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290b.
- Ignition ON.
- Measure the voltage between the ACM C290b-5, circuit 176 (PK/LG), harness side and ground; and between the ACM C290b-6, circuit 179 (OG/RD), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to D8.
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D8 CHECK CIRCUITS 176 (PK/LG) AND 179 (OG/RD) FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect subwoofer amplifier, harness side and the ACM, harness side; and between the suspect subwoofer amplifier, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect subwoofer amplifier and the ACM, and greater than 10,000 ohms between the suspect subwoofer amplifier and ground?
Yes
GO to D12.
No
REPAIR the circuit in question. TEST the system for normal operation.
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D9 CHECK THE AUDIO CIRCUITS TO THE SUSPECT REAR SUBWOOFER
- Ignition OFF.
- Connect: Suspect Subwoofer Amplifier.
- Disconnect: Suspect Rear Subwoofer.
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect rear subwoofer circuits, harness side as follows:
- Is a fluctuating AC voltage present?
Yes
INSTALL a new subwoofer for the suspect subwoofer. REFER to Subwoofer Speaker Subwoofer Speaker. TEST the system for normal operation.
No
GO to D10.
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D10 CHECK THE AUDIO CIRCUITS TO THE SUSPECT SUBWOOFER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Suspect Subwoofer Amplifier C4157b, C4158b, C4159b, or C4160b.
- Ignition ON.
- Measure the voltage between the suspect rear subwoofer, harness side and ground as follows:
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to D11.
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D11 CHECK THE AUDIO CIRCUITS TO THE SUSPECT SUBWOOFER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect rear subwoofer, harness side and the rear amplifier, harness side; and between the suspect rear subwoofer, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect rear subwoofer and the rear subwoofer amplifier, and greater than 10,000 ohms between the suspect rear subwoofer and ground?
Yes
INSTALL a new rear subwoofer amplifier for the suspect amplifier. REFER to Subwoofer Amplifier - Luggage Compartment Subwoofer Amplifier - Luggage Compartment. TEST the system for normal operation.
No
REPAIR the circuit in question. TEST the system for normal operation.
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D12 CHECK FOR CORRECT ACM OPERATION
- Disconnect all the ACM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the ACM 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. REFER to Audio Control Module (ACM) Removal and Replacement. 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.
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