The body control module (BCM) monitors the OFF/RUN/CRANK signal from the ignition switch. The signal is zero when there is no key in the ignition cylinder. The signal is at the 12-volt reference level when a key is placed into the ignition cylinder. When the vehicle operator places the ignition switch in the Run position, the switch supplies 5 volts to the BCM OFF/RUN/CRANK input terminal. During a crank event, the 5-volt signal is passed through an internal resistor in the ignition switch for discrimination of the crank command. If the OFF/RUN/CRANK circuit becomes shorted to B+, ground or the circuit opens, DTC B1441 will set.

Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.

A history DTC may be caused by an intermittent short or open in the OFF/RUN/CRANK circuit or the 5-volt reference circuit. Refer to Testing for Intermittent Conditions and Poor Connections.

Schematic Reference

Power Moding Schematics

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, compare all parameters listed below with the corresponding ignition key position. The PMM Power Mode Parameters table below illustrates the correct state of these input parameters (circuits) in correspondence to the ignition switch position. The circuits which the individual parameters are related to are in parentheses.

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Inspect for an open Ign Switch fuse. 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

•	Run/Crank voltage

•	Accessory wakeup serial data (BCM output)

•	Run/crank ignition 1 voltage (BCM output)

2. Disconnect the harness connector at the ignition switch.
3. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

Important: The ignition switch component test must be preformed before proceeding with this test to verify the integrity of the switch.

4. Perform the ignition switch component test. The test should pass.

⇒	If the ignition switch fails, replace the ignition switch.

5. Ignition OFF, disconnect the X4 and X2 harness connector at the BCM, test for less than 1.0 volt between the following circuit terminals of the BCM and ground.

•	Off/Run/Crank voltage terminal 56

•	5-volt reference terminal 62

•	Accessory voltage terminal C8

•	Run/Crank voltage terminal D3

⇒	If greater than specified, test the circuit for a short to voltage.

6. Test for less than 1.0 ohm between the BCM and the ignition switch on the following circuit terminals.

•	5-volt reference, BCM terminal 62 and ignition switch terminal 6

•	Off/Run/Crank voltage, BCM terminal 56 and ignition switch terminal 5

•	Accessory voltage, BCM terminal C8 and ignition switch terminal 4

•	Run/Crank voltage, BCM terminal D3 and ignition switch terminal 3

⇒	If greater than specified, test the circuit for open/high resistance

7. Test for infinite resistance between the ignition key resistor signal circuit terminal 4 of the BCM and ground.

⇒	If less than specified, test the signal circuit for a short to ground.

8. If all circuits test normal, replace the BCM.

Ignition Switch

1. Ignition OFF, disconnect the harness connector at the ignition switch.
2. Using the Resistance Test table below, check the resistance between the terminals of the ignition switch listed in each switch position.

Perform the Diagnostic Repair Verification after completing the repair.