B1441

DTC B1441

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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1441 Device Ignition OFF, RUN and CRANK Circuit

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description.





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

Test Description

Step 1 - Step 7:

Step 8 - Step 9:

The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the OFF/RUN/CRANK circuit for a short circuit to B+ and ground. Because of the control over powermoding this step must be performed with the switch in the OFF position. Any shorts to ground during this step could be a short to a voltage circuit that is only powered in Run or Accessory. The loads on these circuits would indicate a short to ground, but the cause would have to be traced thorough the OFF/RUN/CRANK circuit and repaired.
4. This step tests the ignition switch contacts of the OFF/RUN/CRANK circuit for merit.
5. This step tests the OFF/RUN/CRANK, +5-volt and +12-volt circuits for an open.