FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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B2500 04 - 02



B2500 04

Microphone Circuit Open







Fault symptom
- "On Star System Malfunction. Contact Service." shown on SID.
- Microphone not functioning.

On-board diagnosis

Type of diagnosis:
- Continuous

Enable criteria:
- Ignition ON.
- Battery voltage must be between 9 - 16 V.
- No starter motor cranking.

Fault criteria:
- Break in microphone circuit.

Checking the wiring harness
- Move the wiring harness at several spots and in several directions to reveal intermittent breaks and short-circuits. Check switches, connectors and crimp connections for oxidation, retracted pins and pin clamping force.

Diagnostic help
- Check that the following MIs/Campaigns have been carried out before starting fault diagnosis:

US Market
- MI No. 391 -2394 - Customer Satisfaction Campaign 1542 1 - Update of OnStar system.
- MI No. 391 -2409 - Customer Satisfaction Campaign 1542 4 - Update of OnStar system.

CA Market
- MI No. 391 -2410 - Customer Satisfaction Campaign 1542 1 - Update of OnStar system.
- MI No. 391 -2408 - Customer Satisfaction Campaign 1542 4 - Update of OnStar system.