B1441

DTC B1370-B1379, B1380-B1389, or B1440-B1443

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B1370 01
- Device Ignition 1 ON and START Circuit Short to Battery

DTC B1370 06
- Device Ignition 1 ON and START Circuit Open

DTC B1380 01
- Device Ignition ACCESSORY Circuit Short to Battery

DTC B1380 02
- Device Ignition ACCESSORY Circuit Short to Ground

DTC B1441 01
- Device Ignition OFF, RUN and CRANK Circuit Short to Battery

DTC B1441 02
- Device Ignition OFF, RUN and CRANK Circuit Short to Ground

Circuit/System Description

The body control module (BCM) monitors the ignition 1 signal, Accessory signal, and the OFF/Run/Crank signal from the ignition switch. When the vehicle operator places the ignition switch in the Off, Accessory, RUN or CRANK position, the switch supplies B+ to the BCM appropriate input terminal.

Conditions for Running the DTC

Voltage is between 9-16 volts.

Conditions for Setting the DTC

* The BCM detects a short to ground in the circuit for greater then 10 seconds.
* The BCM detects a short to battery or an open in the circuit for greater then 10 seconds when the switch is in the OFF position.

Actions Taken When the DTC Sets

* The BCM stores DTC to memory.
* The BCM operates in a fail-safe power mode dependent on the last valid power mode detected and the state of the engine run flag data on the GMLAN serial data communications circuits.
* The other modules on the vehicle operate in a fail-safe power mode dependent on the last valid power mode transmitted by the BCM and the state of the engine run flag on the GMLAN serial data communications circuits.

Conditions for Clearing the DTC

* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Circuit/System Verification

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.






Circuit/System Testing

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 3 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.

Component Testing
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.





If any reading is not as specified, replace the ignition switch.

Repair Instructions

Perform the after completing the repair.

* for BCM replacement, setup, and programming
* Ignition and Start Switch Replacement