CU AMPS / B2500 04

Read the instructions below then start the fault diagnostic procedure.

Symptom: "On Star System Malfunction. Contact Service." shown on the display. Microphone not functioning.

B2500 04

Fault symptom

"On Star System Malfunction. Contact Service." shown on the display.

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 15421 - Update of OnStar system.

MI No. 391-2409 - Customer Satisfaction Campaign 15424 - Update of OnStar system.

CA Market

MI No. 391-2410 - Customer Satisfaction Campaign 15421 - Update of OnStar system.

MI No. 391-2408 - Customer Satisfaction Campaign 15424 - Update of OnStar system.