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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1327 (Automatic Transmission - Mu4 (Introduction, Service & Replacement)) >> Diagnostic Information and Procedures >> Powertrain On Board Diagnostic (OBD) System Check - Automatic Transmission >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 1:  This step determines if the Scan Tool is receiving power through the DLC connector.
  2. 2:  The MIL should illuminate whenever the ignition is ON and the engine is not running.
  3. 3:  This step determines if the PCM is transmitting Class 2 serial data to the DLC and that the Class 2 data circuit is not open or shorted.
  4. 4:  This step determines if a DTC is current or stored in history.
Powertrain On Board Diagnostic (OBD) System Check - Automatic Transmission

Step Action Value(s) Yes No
1 
  1. Install a Scan Tool .
    2. IMPORTANT: Check for applicable service bulletins before proceeding with this test. Perform this test only if there is a driveability complaint or if you have been directed to this table from another section in the service information.
    IMPORTANT: Do not turn the ignition OFF when performing this diagnostic procedure. Do not clear the DTCs unless instructed by this diagnostic procedure.
  2. Turn ON the ignition, with the engine OFF.
Does the Scan Tool turn ON?		 - Go to Step 2  Go to Scan Tool Does Not Power Up in Data Link Communications
2  Is the MIL ON? - Go to Step 3  Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console
3  Attempt to establish communication with the PCM controller modules.
Does the Scan Tool communicate with the PCM control modules?		 - Go to Step 4  Go to Scan Tool Does Not Communicate with VCM/PCM in Data Link Communications
4 
IMPORTANT: Diagnostic Trouble Codes (DTCs), engine performance, and transmission default actions can greatly affect the transmission performance. Ensure that these items are not the cause of a transmission concern.
Use the Scan Tool Capture Info function in order to save or capture/Store Info any DTC Information.Are there any DTCs present?		 - Go to Diagnostic Trouble Code (DTC) List/Type  Go to Symptoms - Automatic Transmission 
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