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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1652 (Body Control System) >> Diagnostic Information and Procedures >> DTC B1420 >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
DTC B1420

Step Action Values Yes No
Schematic Reference:  Body Control System Schematics  
Connector End View Reference: Body Control System Connector End Views 
1 Did you perform the Diagnostic System Check for the system exhibiting the symptom? - Go to Step 2  Go to Control Module References 
2
  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. With a scan tool, observe the battery voltage input parameters in the BCM input data list.
Is the battery voltage input parameter in the specified range?
9.0-16.0 V Go to Step 3  Go to Step 4 
3 Is the DTC set as a current DTC? - Go to Step 7  Go to Diagnostic Aids
4
  1. Disconnect the BCM harness connectors.
  2. Measure the voltage between the battery positive voltage circuit at the BCM harness connector and a good ground. Refer to Circuit Description and Body Control System Schematics .
Is the measured value in the specified range?
9.0-16.0 V Go to Step 6  Go to Step 5 
5 Test the battery positive voltage circuit for a short to ground or an open. Refer to Circuit Description.
Did you find and correct the condition?
- Go to Step 9  Go to BATTERY INSPECTION/TEST (NON-HP2) in Engine Electrical
6 Test the all of ground circuits of the BCM for an open or high resistance.
Did you find and correct the condition?
- Go to Step 9  Go to Step 7 
7 Inspect for poor connections at the module 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 9  Go to Step 8 
8
IMPORTANT: Perform the module programming or setup procedure if required.
Replace the BCM. Refer to Body Control Module Replacement .Did you complete the replacement?
- Go to Step 9  -
9 Operate the system in order to verify the repair.
Did you find and correct the condition?
- System OK Go to Step 2