2010 Cadillac CTS Sedan AWD V6-3.6L Page 387
Circuit/System Verification
1. Verify that the following DTCs are not set: U1814, B1428.
瀚慖f either of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. With a scan tool, access BCM, Power Mode data display list and compare all parameters listed with the corresponding ignition key position.
The PMM Power Mode Parameters table below illustrates the correct state of these input parameters in correspondence to the ignition switch
position. The circuits which the individual parameters are related to are in parentheses.
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Connect a test lamp between each fuse test terminal of the ignition switch B+ circuit fuse and ground. The test lamp should illuminate.
瀚慖f the test lamp does not illuminate, test the circuits listed below for a short to ground. If all circuits test OK, replace the BCM.
* B+ terminal 2
* Ignition terminal 1
* Ignition terminal 3
* Ignition terminal 4
* Ignition, BCM terminal 19, X4
* Ignition, BCM terminal 21, X4
2. Disconnect the harness connector at the ignition switch.
3. Connect a test lamp between the B+ circuit terminal 2 and ground. The test lamp should illuminate.
瀚慖f the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
Important: The ignition switch component test must be performed before proceeding with this test to verify the integrity of the
switch.
4. Perform the ignition switch component test. Verify the switch passes the test.
瀚慖f the ignition switch does not test normal, replace the ignition switch.
5. Disconnect the X1 harness connector at the BCM, test for less than 1.0 V between the circuit terminals of the BCM listed below and ground:
* Ignition terminal 4
* Ignition terminal 21
* Ignition terminal 21, X4
瀚慖f greater than specified, test the circuit for a short to voltage.
6. Test for less than 1.0 Ohms between the BCM and the ignition switch on the circuits listed below:
* Ignition terminal 2, X1 and ignition switch terminal 4
* Ignition terminal 21, X1 and ignition switch terminal 3
* Ignition terminal 21, X4 and ignition switch terminal 1
瀚慖f greater than specified, test the circuit for open/high resistance
7. If all circuits test normal, replace the BCM.
