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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 502 (BODY CONTROL SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B1440: POWER MODE MASTER INPUT CIRCUITS MISMATCHCONDITIONS FOR CLEARING THE DTC
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8

Conditions for Clearing the DTC

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Conditions for Clearing the DTC
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
  • 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.
DTC B1440

Step Action Yes No
Schematic Reference: Body Control System Schematics 
Connector End View Reference: Master Electrical Component List
1 Preform the Diagnostic System Check for the system exhibiting the symptom. Refer to Control Module References .
Did you perform the Diagnostic System Check?		 Go to Step 2  Go to Control Module References 
2
  1. Install a scan tool.
  2. Turn the ignition switch to OFF.
  3. With a scan tool, monitor the following in Body Control Module, Data Display, Inputs:
    • Ignition 0
    • Ignition 1
    • Ignition Accessory
Does the scan tool match the power mode table for the current ignition switch position?		 Go to Step 3  Go to Step 7 
3
  1. Install a scan tool.
  2. Turn the ignition switch to ACC.
  3. With a scan tool, monitor the following in Body Control Module, Data Display, Inputs:
    • Ignition 0
    • Ignition 1
    • Ignition Accessory
Does the scan tool match the power mode table for the current ignition switch position?		 Go to Step 4  Go to Step 9 
4
  1. Install a scan tool.
  2. Turn the ignition switch ON, with the engine OFF.
  3. With a scan tool, monitor the following in Body Control Module, Data Display, Inputs:
    • Ignition 0
    • Ignition 1
    • Ignition Accessory
Does the scan tool match the power mode table for the current ignition switch position?		 Go to Step 5  Go to Step 9 
5
IMPORTANT: The engine may start in this step. Turn the engine OFF immediately after reviewing the input data.
  1. Install a scan tool.
  2. Turn the ignition switch to START.
  3. With a scan tool, monitor the following in Body Control Module, Data Display, Inputs:
    • Ignition 0
    • Ignition 1
    • Ignition Accessory
Does the scan tool match the power mode table for the current ignition switch position?		 Go to Step 6  Go to Step 9 
6 Were any of the ignition switch inputs active when they were not called for in the previous steps? Go to Step 7  Go to Step 12 
7
  1. Disconnect the ignition switch harness connectors.
  2. Install a scan tool.
  3. With a scan tool, monitor the following in Body Control Module, Data Display, Inputs:
    • Ignition 0
    • Ignition 1
    • Ignition Accessory
Does the scan tool indicate that any of the Ignition 0, Ignition 1 or Ignition Accessory inputs are active?		 Go to Step 8  Go to Step 10 
8
  1. Disconnect the BCM harness connectors.
  2. Test the suspect ignition switch input circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 15  Go to Step 12 
9
  1. Disconnect the ignition switch connectors.
  2. Install a 3A fused jumper between the suspect circuits and an ignition switch B+ supply.
  3. With a scan tool, monitor the suspect circuits in Body Control Module, Data Display, Inputs:
    • Ignition 0
    • Ignition 1
    • Ignition Accessory
Does the scan tool indicate that the suspect circuits are now active?		 Go to Step 10  Go to Step 11 
10 Inspect for poor connections at the ignition switch harness connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 15  Go to Step 13 
11
  1. Disconnect the BCM harness connectors.
  2. Test the suspect ignition switch input circuits for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 15  Go to Step 12 
12 Inspect for poor connections at the BCM harness connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 15  Go to Step 14 
13 Replace the ignition switch. Refer to Ignition Switch Replacement in Steering Wheel and Column.
Did you complete the replacement?		 Go to Step 15  -
14
IMPORTANT: Perform the set up procedure for the BCM.
Replace the BCM. Refer to Body Control Module Replacement .Did you complete the replacement?		 Go to Step 15  -
15
  1. Reconnect all components.
  2. Use the scan tool in order to clear DTCs.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 System OK Go to Step 2 
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.