Test C: The Subwoofer Is Inoperative/Does Not Operate Correctly - Audiophile

PINPOINT TEST C: THE SUBWOOFER IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - AUDIOPHILE

Normal Operation
The subwoofer speaker is powered by a separate subwoofer amplifier. For wagons, the subwoofer speaker is integral to the subwoofer enclosure. For sedans, there are 2 subwoofer speakers connected to the subwoofer amplifier through circuits VME01 (GN/VT), RME01 (GY), VME02 (VT), and RME02 (YE). The subwoofer receives audio signals from the audio unit through circuits VME22 (VT/GN) and RME22 (GN/WH). The subwoofer amplifier receives voltage (at all times) through circuit SBP38 (BN/RD), and ground through circuit GD148 (BK/YE).

To enable the subwoofer amplifier, the audio unit 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 audio unit. In the event of an overload, the audio unit clips the audio output signal to the amplifier (heard as distortion), in order to prevent damage to the amplifier and speakers.

The clip/enable status is based on the following voltages, as detected by the audio unit:
- 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 from the subwoofer.

DTC B1154 (Subwoofer #1 Short to Ground) - sets when a short to ground is detected on circuit RME22 (GN/WH) or VME22 (VT/GN). This DTC only sets during the on-demand self-test.

DTC B1155 (Subwoofer #1 Short to Battery) - sets when a short to voltage is detected on circuit RME22 (GN/WH) or VME22 (VT/GN). This DTC only sets during the on-demand self-test.

DTC B1158 (Subwoofer #2 Open) - sets when an open is detected on circuit RME22 (GN/WH) or VME22 (VT/GN). This DTC only sets during the on-demand self-test.

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

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Subwoofer amplifier
- Subwoofer speaker
- Audio unit

C1-C2:

C3-C5:

C6-C8:

C8-C10:

C10-C12:

C13-C14: