Circuit Description
The OnStar® Interface Module Communication (CIM) monitors circuit 654 to
the microphone for proper function. If circuit 654 is 9 volts, this indicates the
microphone is present and functioning properly. If the CIM detects a low signal on
circuit 654, the CIM will sample the input 5 times within .5 second if low for all
samples then fail DTC B2455. Circuit 655 provides voltage to the microphone. An open
or high resistance in circuit 655 will also fail DTC B2455.
Conditions for Setting the DTC
| • | If input is low from microphone, the CIM will check 5 times within 0.5
seconds, and the condition must be present for all samples then fail DTC B2455 as
a current code. |
| • | Illuminate the red OnStar® LED. |
| • | This test runs every 10 seconds. |
Diagnostic Aids
Check for loose of improper connections at the microphone and the OnStar®
CIM.
