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Diagnostic Procedures

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Perform the Fuel System Diagnosis to check for leaks before proceeding. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  3. Attempt to start the engine. Does the engine start and run? If yes, go to next step. If no, go to step  8.
  4. Install the J 44638 Vacuum Gauge on the fuel fitting located on the right side front of the engine. Start and run the engine at idle. Observe the vacuum gauge while increasing RPM slowly to 3000 RPM in park or neutral. Does the vacuum measure less than 5 in. through the entire RPM range? If yes, go to step  7. If no, go to next step.
  5. Replace the fuel filter. After repair, go to next step.
  6. Start and run the engine at idle. Observe the vacuum gauge while increasing RPM slowly to 3000 RPM in park or neutral. Does the vacuum measure less than 5 in. through the entire RPM range? If yes, go to step  14. If no, go to step  10.
  7. Start and idle the engine. Observe the Actual Fuel Rail Pressure with a scan tool. Does the Actual Fuel Rail Pressure measure less than or equal to 23 MPa? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  8. Disconnect the FRP sensor. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Does the Actual Fuel Rail Pressure measure more than 175 MPa? If yes, go to next step. If no, go to step  13.
  9. Attempt to start the engine with the FRP sensor disconnected. Does the engine start and run? If yes, go to step  11. If no, diagnose fuel system high pressure side. See FUEL SYSTEM DIAGNOSIS - HIGH PRESSURE SIDE under FUEL SYSTEMS (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS -EXCEPT TRACKER article.
  10. Check for a restriction in the fuel supply system. Repair as necessary. After repairs, go to step  14.
  11. Check for poor connections at the FRP sensor. Repair as necessary. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  12. Replace the FRP sensor. After repairs, go to step  14.
  13. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See ENGINE CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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