Test D: The Subwoofer Is Inoperative/Does Not Operate Correctly (Audiophile)

PINPOINT TEST D: THE SUBWOOFER IS INOPERATIVE/DOES NOT OPERATE CORRECTLY (AUDIOPHILE)

Normal Operation
The subwoofer speaker is powered by a separate subwoofer amplifier. To enable the subwoofer amplifier, the audio control module (ACM) sends voltage through the enable/clip circuit SME23 (VT/RD). The circuit acts as both an output (to enable the amplifier) and an input (to detect an amplifier overload condition). A variable resistor in the subwoofer amplifier modifies the voltage signal from the ACM. In the event of an overload, the ACM clips the audio output signal to the amplifier (heard as distortion), in order to prevent damage to the amplifier and speakers. The subwoofer amplifier receives voltage through circuit SBB22 (BN/RD), and ground through circuit GD114 (BK/BU).

The clip/enable status is based on the following voltages, as detected by the ACM:
- Less than 0.4 volts: amplifier disabled
- Between 3.8 and 6.7 volts: amplifier enabled
- Greater than 8.5 volts: amplifier clipped

An open in circuit SME23 (VT/RD) will cause the subwoofer to produce no sound, because the enable signal will not reach the subwoofer amplifier. A short to ground or short to voltage can cause severe distortion to be heard in the subwoofer.

- DTC B2913 (Audio Subwoofer Not Connected) - sets when the ACM does not detect the subwoofer through circuit SME23 (VT/RD) during the subwoofer connection test (part of the ACM self-test).

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Subwoofer
- ACM

D1:

D2-D4:

D4-D6:

D6-D8:

D8-D9: