Pinpoint Test 4: The Subwoofer Is Inoperative/Does Not Operate Correctly

PINPOINT TEST 4: THE SUBWOOFER IS INOPERATIVE/DOES NOT OPERATE CORRECTLY

Normal Operation

The subwoofer amplifier receives voltage through circuit (BR/R) and ground through circuit (B/G). The subwoofer speaker and subwoofer amplifier are integral to the enclosure and cannot be replaced individually; however, the subwoofer speaker is only replaceable as an assembly with the enclosure and subwoofer amplifier.To enable the subwoofer amplifier, the audio control module (ACM) sends voltage through the enable/clip circuit (V/R). 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 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 (V/R) 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 B1155 (Subwoofer #1 Short to Battery) - sets when a short to voltage is detected on circuit (V/R). This DTC only sets during the on-demand self-test.
- DTC B1158 (Subwoofer #2 Open) - sets when a open is detected on circuit (V/R). This DTC only sets during the on-demand self-test.
- DTC B2913 (Audio Subwoofer Not Connected) - sets when the ACM does not detect the subwoofer through circuit (V/R) during the subwoofer connection test (part of the ACM self-test).

Possible Causes
- Fuse
- Wiring, terminals or connectors
- Subwoofer
- ACM

Diagnostic Procedure

CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

Step 1-Step 5:

Step 6-Step 9:

Step 10: