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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1412 (Antilock Brake System And Traction Control System) >> Diagnostic Information and Procedures >> DTC C0265 or C0266: EBCM Relay Circuit >> Test Description

Test Description

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The numbers below refer to the step numbers on the diagnostic table.

  1. 4:  This step tests if the battery positive voltage circuit can supply adequate power to the system relay.
  2. 7:  A shorted ABS pump motor or shorted motor circuitry may damage the contacts within the system relay. Follow this step to prevent damage to a replacement EBCM.
DTC C0265 or C0266 Diagnostic Test

Step Action Values Yes No
Schematic Reference:  ABS Schematics  
Connector End View Reference:  ABS Connector End Views  
1 Did you perform the ABS Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - ABS 
2
  1. Use a scan tool in order to clear the DTCs.
  2. Use the scan tool in order to perform an ABS Function Test.
Does DTC C0266 set?		 - Go to Step 7  Go to Step 3 
3 Does DTC C0265 set? - Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn OFF the ignition.
  2. Disconnect from the EBCM, the harness connector containing the battery positive voltage circuit.
  3. Connect a test lamp between the battery positive voltage circuit and a good ground.
Does the test lamp illuminate?		 - Go to Step 6  Go to Step 5 
5 Repair the open in the battery positive voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 11  -
6 Inspect for poor connections at the harness connector of the EBCM. 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 11  Go to Step 7 
7 
IMPORTANT: It may be necessary to separate the EBCM from the BPMV to gain access to the pump motor pigtail connector. If so, refer to Electronic Brake Control Module Replacement .
  1. Disconnect from the EBCM, the ABS pump motor pigtail connector.
  2. Use a DMM in order to measure the resistance across the ABS pump motor.
Does the resistance measure within the specified range?		 0.3-1.0 Ω Go to Step 8  Go to Step 10 
8 Use a DMM in order to measure the resistance between the high side of the pump motor and a good ground.
Does the resistance measure less than the specified value?		 0L Go to Step 10  Go to Step 9 
9
IMPORTANT: Use the scan tool in order to perform the Tire Size Calibration procedure and the Trim Level Calibration procedure, if applicable.
Replace the EBCM. Refer to Electronic Brake Control Module Replacement .Did you complete the replacement?		 - Go to Step 11  -
10
IMPORTANT: Use the scan tool in order to perform the Tire Size Calibration procedure and the Trim Level Calibration procedure, if applicable.
Replace the EBCM and the BPMV. Refer to Electronic Brake Control Module Replacement  and Brake Pressure Modulator Valve (BPMV) Replacement .Did you complete the replacements?		 - Go to Step 11  -
11
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 - Go to Step 2  System OK
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