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Home >> Pontiac >> 2001 >> Firebird Base, 2D Convertible, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0401: Insufficient EGR Flow >> Diagnostic Procedures

Diagnostic Procedures

  1. If powertrain diagnostic system check was performed, go to next step. If powertrain diagnostic system check was not performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under DIAGNOSTIC SYSTEM CHECKS. After performing powertrain diagnostic system check, go to next step.
  2. If any MAP sensor DTCs are set, diagnose those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no MAP DTCs are set, go to next step.
  3. Check exhaust system for modifications or leaks. Replace or repair as necessary. After repairs, go to step  7. If exhaust is okay, go to next step.
  4. Check for leaks at EGR pipe and gasket at EGR valve. Repair or replace as necessary. After repairs, go to step  7. If EGR valve gasket and pipe are okay, go to next step.
  5. Remove EGR valve. Check for restrictions or blockage of EGR ports or pintle. Repair or replace as necessary. After repairs, go to step  7. If no restrictions are found, go to next step.
  6. Remove EGR valve. Check for restrictions or blockage of EGR intake manifold port or exhaust pipe. Repair or replace as necessary. After repairs, go to next step. If no restrictions are found, go to DIAGNOSTIC AIDS .
  7. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step  2.
  8. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.
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