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Home >> Pontiac >> 2001 >> Aztek Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 737 (Emission System) >> EGR Valve Inspection >> EGR Control Inspection >> Using WDS or equivalent

Using WDS or equivalent

WARNING: This page is about a different car, the 2004 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect the WDS or equivalent to the DLC-2.
    Fig 1: Locating Data Link Connector (DLC-2)
    G00973069Courtesy of MAZDA MOTORS CORP.
  2. Start the engine.
  3. Using the "SEGRP" simulation function, operate with Steps 0  (idling) to 52  and verify that the engine speed becomes unstable or the engine stalls.
    • If the engine speed does not change, perform the following procedure:
      1. Stop the engine.
      2. Remove the EGR valve. (See EGR VALVE REMOVAL/INSTALLATION .)
      3. Connect the EGR valve connector.
      4. Turn the ignition switch to the ON position.
      5. Using the "SEGRP" simulation function, verify that it operates with Steps 0  (idling) to 52. 
        • If the EGR valve operates, inspect the following:
          • EGR pipe clogging
        • If the EGR valve does not operate, inspect the following:
          • PCM terminal voltage
            • EGR valve signal
          • EGR valve (If it is stuck or not moving smoothly, replace it with a new one.)
    • Warm up the engine to normal operating temperature.
    • Place the vehicle on the chassis dynamometer.
    • Monitor the following signals using the PID/data monitor.
      • EGR valve step number (SEGRP)
      • Engine speed (RPM)
      • Vehicle speed (VSS)
      • Throttle position (TP)
      • Engine coolant temperature (ECT)
    • Verify that the EGR valve step number is 0  during idle.
    • Verify that the EGR valve step number increases when the accelerator pedal is depressed to increase the vehicle speed.
      • If it does not increase, inspect the following using the PID/data monitor.
        • Vehicle speed (VSS)
        • Throttle position (TP)
        • Engine coolant temperature (ECT)
    • Stop the vehicle and verify that the EGR valve step number is 0  during idle.