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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 423 (ENGINE CONTROL SYSTEM SELF-DIAGNOSTICS - 3.8L)DIAGNOSTIC TESTSDTC P0401: EGR SYSTEM INSUFFICIENT FLOWCONDITIONS FOR RUNNING DTC
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Conditions For Running DTC

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Conditions For Running DTC
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
  • DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0201-P0206, P0300, P0336, P0403, P0404, P0502, P0503, P0506, P0507, P1106, P1107, P1112, P1113, P1114, P1115, P1121, P1122, P1374, or P1404 are not set.
  • The ignition 1 signal parameter is 11-18 volts.
  • A/C status does not change.
  • Transaxle range does not change.
  • TP angle is less than one percent.
  • Intake Air Temperature (IAT) is -40 to 248°F (-40 to 140°C).
  • Engine Coolant Temperature (ECT) is more than 167°F (75°C).
  • Engine speed is 1100-1400 RPM.
  • The MAP sensor parameter is 17-43 kPa.
  • The MAF sensor parameter does not change more than 2 grams per second.
  • The BARO parameter is more than 74 kPa.
  • The TP sensor parameter is less than 1 percent.
  • The VSS parameter is more than 28 MPH. during deceleration.
  • Vehicle will need to be driven above 50 MPH, and then allowed to decelerate. When the vehicle is decelerating while meeting all of the criteria, the PCM will enable the test to run. As the test is running, you will see the desired EGR parameter and the EGR position sensor on the scan tool change from zero to a calibrated value above zero. Additionally, the EGR Flow Test Count parameter on the scan tool will increment when each EGR flow test is completed.
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