B1441

DTC B1441

Diagnostic Instructions

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



DTC Descriptors
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 Description

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.


Conditions for Running the DTC

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


Conditions for Setting the DTC

* The BCM detects a short to ground in the OFF/RUN/CRANK voltage circuit when the ignition switch is in RUN or CRANK.
* The BCM detects a short to battery or an open in the OFF/RUN/CRANK circuit.
* Any of the conditions above must be present for more than 10 seconds.



Action 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.



Diagnostic Aids

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 (Component Tests and General Diagnostics) .


Reference Information
Schematic Reference

Ignition Lock Schematics (Ignition Lock Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Electronic Park Lock Description and Operation (Electronic Park Lock Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information.


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 2 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 (Service and Repair)