Captiva

Power Mode Mismatch

The vehicle power mode master is the body control module (BCM). The ignition switch is a low current switch with multiple discrete circuits to the BCM. The BCM logic uses the ignition switch positions to identify the operator's desired power mode and activate specific discrete signals, and serial data messages for the operation of different subsystems as necessary. Other modules which have switched voltage inputs may operate in a default mode if the power mode master serial data message does not match what the individual module can detect from its own connections.

The power mode master will activate relays and other direct outputs of the power mode master as needed according to the calculated power mode. Some relays controlled by the BCM are switched ignition voltage outputs that are pass through circuits within the BCM directly from the ignition switch. If these circuits short to ground, the B+ circuit fuse to the ignition switch will open.

B1370 01, B1370 04

Ignition switch is in the RUN or CRANK positions.

B1380 01, B1380 04

Ignition switch is in the RUN or ACCESSORY positions.

B1441 01, B1441 04

Ignition switch is in the CRANK position.

B1370 01

Ignition circuit is shorted to voltage.

B1370 04

B1380 01

Accessory circuit is shorted to voltage.

B1380 04

B1441 01

Off/run/crank signal circuit is shorted to voltage.

B1441 04

Off/run/crank signal circuit is open.

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

Power Mode Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

With a scan tool, access Power Mode data display list and compare all parameters listed with the corresponding ignition key position. The Power Mode Parameters table below illustrates the correct state of these input parameters in correspondence to the S39 ignition switch position. The circuits which the individual parameters are related to are in parentheses.

1. Disconnect the harness connector at the S39 ignition switch.
2. Verify that a test lamp illuminates between B+ circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the ignition circuits listed below for a short to ground.

Note: To help isolate a short to ground, it may be necessary to disconnect modules that are connected to the following circuits:

•	Terminal 1

•	Terminal 3

3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 5 and ground.

⇒	If less than 4.8 V, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒	If greater than 5.2 V, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. Verify the scan tool ignition switch signal voltage is less than 4.2 V.

⇒	If greater than 4.2 V, test the ignition switch signal circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the BCM.

5. Install a 3 A fused jumper wire between the ignition switch signal circuit terminal 4 and the 5 V reference circuit terminal 5. Verify the scan tool Ignition Switch Signal Voltage parameter is greater than 3 V.

⇒	If less than 3 V, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

6. Connect the harness connector at the S39 ignition switch.
7. Ignition OFF, key out, disconnect the X5 harness connector at the BCM. Verify that a test lamp does not illuminate between the ignition circuit terminals listed below and ground:

•	Terminal 14

•	Terminal 21

⇒	If the test lamp illuminates, test the ignition circuits for a short to voltage. If the circuit tests normal, replace the S39 ignition switch.

8. Ignition in the ACCESSORY position, verify that a test lamp illuminates between the terminal 14 and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. If the circuit tests normal, replace the S39 ignition switch.

9. Ignition in the CRANK position, verify that a test lamp illuminates between terminal 21 and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. If the circuit tests normal, replace the S39 ignition switch.

10. If all of the circuits test normal, replace the BCM.

Ignition Switch

1. Ignition OFF, disconnect the harness connector at the S39 ignition switch.
2. Verify the resistance between the terminals listed below match for each S39 ignition switch position.

⇒	If not the specified value, replace the S39 ignition switch.

Perform the Diagnostic Repair Verification after completing the repair.