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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 100 (Engine Control System Self-Diagnostics - 3.8L) >> Diagnostic Tests >> DTC P0403: EGR Solenoid Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

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  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Install scan tool. Turn ignition on, engine off. Using scan tool, command EGR from zero to 100 percent. Does the EGR position sensor remain close to the Desired EGR Position at all commanded positions? If yes, go to next step. If no, go to step  4.
  3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC or as close to FREEZE FRAME/FAILURE RECORDS data as possible. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition off. Disconnect EGR. Turn ignition on, engine off. Probe the EGR solenoid high control circuit with a test lamp connected to a good ground. Use a scan tool in order to command the EGR between 0 percent and 10 percent. Does the test lamp turn on and off with each command? If yes, go to next step. If no, go to step  6.
  5. Connect a test lamp between the high control circuit of the solenoid and the low control circuit of the solenoid. Use a scan tool in order to command the EGR between 0 percent and 10 percent. Does the test lamp turn on and off with each command? If yes, go to step  10. If no, go to step  9.
  6. Does the test lamp remain illuminated with each command? If yes, go to step  8. If no, go to next step.
  7. Check EGR solenoid high control circuit for a short to ground or an open. Did you find and correct the condition? If yes, go to step  14. If no, go to step  11.
  8. Check EGR solenoid high control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  14. If no, go to step  11.
  9. Check EGR solenoid low control circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  14. If no, go to step  11.
  10. Check EGR connector for poor connections. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  11. Check PCM connectors for poor connections. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  12. Replace EGR. After repairs, go to step  14.
  13. Replace PCM. Program replacement PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  14. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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