CU AMPS / U1500 08

Read the instructions below then start the fault diagnostic procedure.

Symptom: "On Star System Malfunction. Contact Service." shown on the display. No phone function.

U1500 08

Fault symptom

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

No phone function.

On-board diagnosis

Enable criteria:

Ignition ON.

Battery voltage must be between 9 - 16 V.

Fault criteria:

Control module on-board diagnostics has detected an internal communication fault.

Diagnostic help

Change the control module.

See "Before changing a control module".

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.

Diagnostic help

Diagnosis regards:

To locate electrical faults in the control module internal electronics.

Functions in the diagnostic tool related to the fault:

See menu "All - Add/Remove"