Circuit/System Testing
WARNING: This page is about a different car, the 2006 Buick Lucerne. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Inspect the Ign Switch fuse for open. The fuse should be OK.
- If the fuse is open, test the following circuits for a short to ground, if all circuits test OK, replace the BCM.
- Battery positive voltage of the ignition switch
- Accessory voltage
- Off/Run crank voltage
- Ignition 1 voltage
- Accessory wakeup serial data
- Run/crank ignition 1 voltage
- Disconnect the ignition switch connector.
- Test for battery positive voltage between the battery positive voltage circuit of the ignition switch and ground.
- If less than battery positive voltage, repair the circuit for an open/high resistance
- Perform the ignition switch component test.
- If the ignition switch fails, replace the ignition switch.
- Ignition OFF, disconnect BCM connector C1, test for less than 1.0 volt between the following circuits of the BCM and ground.
- Ignition key resistor signal
- Off/Run crank
- Accessory voltage
- Ignition 1 voltage
- If more than 1.0 volt, repair the circuit for a short to voltage.
- Test for less than 1 ohm of resistance between the BCM and the ignition switch on the following circuits.
- Ignition key resistor signal
- Off/Run crank
- Accessory voltage
- Ignition 1 voltage
- If greater than 5 ohms, repair the circuit for open/high resistance
- Test for infinite resistance between the ignition key resistor signal circuit of the BCM and ground.
- If less than infinite resistance, repair the signal circuit for a short to ground.
- Replace the BCM.
IMPORTANT:
The ignition switch component test must be preformed before proceeding with this test to verify the integrity of the switch.