Pinpoint Test C: The Subwoofer Is Inoperative/Does Not Operate Correctly - Front Subwoofer
Information and Entertainment System
Pinpoint Tests
Pinpoint Test C: The Subwoofer is Inoperative/Does Not Operate Correctly - Front Subwoofer
Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information. Diagrams By Number
Normal Operation
The front subwoofers are powered by a separate subwoofer amplifier for each subwoofer speaker. The enable/clip circuit 173 (DG/VT) carries out 2 functions: to turn on the subwoofer amplifiers, and monitor an overload condition to the subwoofer amplifier. In the event of an overload, the Audio Control Module (ACM) clips the audio output signal to the subwoofer amplifiers (heard as distortion). The front subwoofer amplifiers receive voltage through circuit 829 (WH/VT), 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 C: THE SUBWOOFER IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - FRONT 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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C1 CHECK CIRCUIT 829 (WH/VT) FOR VOLTAGE
- Ignition OFF.
- Disconnect: Left Front Subwoofer Amplifier C2993a and Right Front Subwoofer Amplifier C2994a.
- Measure the voltage between the left front subwoofer amplifier C2993a-5, circuit 829 (WH/VT), harness side and ground; and between the right front subwoofer amplifier C2994a-5, circuit 829 (WH/VT), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to C2.
No
VERIFY the Bussed Electrical Center (BEC) fuse 16 (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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C2 CHECK CIRCUIT 1204 (BK/OG) FOR AN OPEN
- Measure the resistance between the left front subwoofer amplifier C2993a-2, circuit 1204 (BK/OG), harness side and ground; and between the right front subwoofer amplifier C2994a-2, circuit 1204 (BK/OG), harness side and ground.
- Are the resistances less than 5 ohms?
Yes
GO to C3.
No
REPAIR the circuit in question. TEST the system for normal operation.
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C3 CHECK CIRCUIT 173 (DG/VT) FOR VOLTAGE
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the voltage between the left front subwoofer amplifier C2993a-1, circuit 173 (DG/VT), harness side and ground; and between the right front subwoofer amplifier C2994a-1, circuit 173 (DG/VT), harness side and ground.
- Is the voltage between 3.8 and 6.7 volts at both amplifiers?
Yes
GO to C6.
No
If the voltage is incorrect at one amplifier only, REPAIR the circuit in question. TEST the system for normal operation.
If the voltage is incorrect at both amplifiers, GO to C4.
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C4 CHECK CIRCUIT 173 (DG/VT) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290b.
- Ignition ON.
- Measure the voltage between the left front subwoofer amplifier C2993a-1, circuit 173 (DG/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to C5.
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C5 CHECK CIRCUIT 173 (DG/VT) FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the left front subwoofer amplifier C2993a-1, circuit 173 (DG/VT), harness side and the ACM C290b-4, circuit 173 (DG/VT), harness side; and between the left front subwoofer amplifier C2993a-1, circuit 173 (DG/VT), harness side and ground.
- Is the resistance less than 5 ohms between the left front subwoofer amplifier and the ACM, and greater than 10,000 ohms between the left front subwoofer amplifier and ground?
Yes
GO to C13.
No
REPAIR the circuit. TEST the system for normal operation.
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C6 CHECK THE AUDIO SIGNALS TO THE FRONT SUBWOOFER AMPLIFIER
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the left front subwoofer amplifier C2993a-7, circuit 167 (BN/OG), harness side and the left front subwoofer amplifier C2993a-8, circuit 168 (RD/BK), harness side; and between the right front subwoofer amplifier C2994a-7, circuit 167 (BN/OG), harness side and the right front subwoofer amplifier C2994a-8, circuit 168 (RD/BK), harness side.
- Is a fluctuating AC voltage present at both amplifiers?
Yes
GO to C10.
No
If the voltage is incorrect at one amplifier only, GO to C7 .
If the voltage is incorrect at both amplifiers, GO to C8 .
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C7 CHECK CIRCUIT 167 (BN/OG) ) FOR AN OPEN
NOTE: Carry out this step only for the inoperative subwoofer.
- Ignition OFF.
- Disconnect: ACM C290b.
- Measure the resistance between the left front subwoofer amplifier C2993a-7, circuit 167 (BN/OG), harness side and the ACM C290b-1, circuit 167 (BN/OG), harness side; or between the right front subwoofer amplifier C2994a-7, circuit 167 (BN/OG), harness side and the ACM C290b-1, circuit 167 (BN/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
REPAIR circuit 168 (RD/BK). TEST the system for normal operation.
No
REPAIR circuit 167 (BN/OG). TEST the system for normal operation.
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C8 CHECK CIRCUITS 167 (BN/OG) AND 168 (RD/BK) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290b.
- Ignition ON.
- Measure the voltage between the left front subwoofer amplifier C2993a-7, circuit 167 (BN/OG), harness side and ground; and between the left front subwoofer amplifier C2993a-8, circuit 168 (RD/BK), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to C9.
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C9 CHECK CIRCUITS 167 (BN/OG) AND 168 (RD/BK) FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the left front subwoofer amplifier, harness side and the ACM, harness side; and between the left front subwoofer amplifier, harness side and ground as follows:
- Is the resistance less than 5 ohms between the left front subwoofer amplifier and the ACM, and greater than 10,000 ohms between the left front subwoofer amplifier and ground?
Yes
GO to C13.
No
REPAIR the circuit in question. TEST the system for normal operation.
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C10 CHECK THE AUDIO CIRCUITS TO THE SUSPECT FRONT SUBWOOFER
- Ignition OFF.
- Connect: Left Front Subwoofer Amplifier C2993a and Right Front Subwoofer Amplifier C2994a.
- Disconnect: Left Front Subwoofer C536 or Right Front Subwoofer C628.
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect front 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 C11.
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C11 CHECK THE AUDIO CIRCUITS TO THE SUSPECT SUBWOOFER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Left Front Subwoofer Amplifier C2993b and Right Front Subwoofer Amplifier C2994b.
- Ignition ON.
- Measure the voltage between the suspect front 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 C12.
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C12 CHECK THE AUDIO CIRCUITS TO THE SUSPECT SUBWOOFER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect front subwoofer, harness side and the front amplifier, harness side; and between the suspect front subwoofer, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect front subwoofer and the front subwoofer amplifier, and greater than 10,000 ohms between the suspect front subwoofer and ground?
Yes
INSTALL a new front subwoofer amplifier for the suspect amplifier. REFER to Subwoofer Amplifier - Door Subwoofer Amplifier - Door. TEST the system for normal operation.
No
REPAIR the circuit in question. TEST the system for normal operation.
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C13 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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