CU AMPS / B2476 02

Read the instructions below then start the fault diagnostic procedure.

Symptom: "On Star System Malfunction. Contact Service." shown on the display. OnStar buttons not working.

B2476 02

Fault symptom

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

OnStar buttons not working.

On-board diagnosis

Type of diagnosis:

Continuous

Enable criteria:

Ignition ON.

Battery voltage must be between 9 - 16 V.

Fault criteria:

Control module input short circuit to ground.

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.