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Home >> Chevrolet >> 1997 >> C3500 HD 7.4 J, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 3 (Engine Controls - Tests W/Codes - 6.5L) >> Diagnostic Trouble Codes >> DTC P1406 - EGR Valve Position >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different variant/trim than selected.
  1. Capture and record freeze frame and failure records data. Perform Powertrain ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the BASIC TESTING - 6.5L DIESEL article. Then go to next step.
  2. Check if any other DTCs are set. If any other DTCs are set, go to appropriate DTC. If any other DTCs are not set, go to next step.
  3. Check for restriction in vacuum line from EGR valve to vacuum "T" fitting. Check for faulty EGR valve. Repair or replace as necessary. After repairs, go to next step.
  4. After repairs, reset EGR Adaptive Learn Matrix (ALM) cells using scan tool. After resetting EGR ALM cells, go to next step.
  5. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P1406. Operate vehicle within the 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, repeat step 2).
  6. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
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