Circuit/System Testing
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the X2 harness connector at the audio amplifier.
- Ignition ON, test for a momentary AC voltage between the signal circuit terminal B12 and the signal circuit terminal A12 when the white dot button on the OnStar keypad is pressed.
- If a momentary AC voltage was not present, replace the VCIM.
- Ignition OFF, disconnect the X2 harness connector at the VCIM.
- Verify that a test lamp does not illuminate between B+ and the signal circuit terminal 1.
- If the test lamp illuminates, test the signal circuit for a short to ground.
- Verify that a test lamp does not illuminate between B+ and the signal circuit terminal 2.
- If the test lamp illuminates, test the signal circuit for a short to ground.
- Test for less than 1 ohm between the signal circuit terminal 1 and the audio amplifier X2 harness connector terminal B12.
- If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance.
- Test for less than 1 ohm between the signal circuit terminal 2 and the audio amplifier X2 harness connector terminal A12.
- If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance.
- If all circuits test normal, replace the VCIM.