LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 87 (Engine Controls - Self-Diagnostics - 6.6L Diesel) >> Diagnostic Tests >> DTC P1093: Fuel Rail Pressure Out Of Range >> Diagnostic Procedures

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. Is DTC P0168 also set? If yes, see DTC P0168: FUEL TEMPERATURE SENSOR HIGH . If no, go to next step.
  3. Attempt to start the engine. Does the engine start and idle? If yes, go to next step. If no, see ENGINE CRANKS BUT DOES NOT RUN in appropriate BASIC DIAGNOSTIC PROCEDURES article.
  4. Turn ON the ignition, with the engine OFF. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Is the Actual Fuel Rail Pressure Parameter 1.2-1.4 MPa? If yes, go to next step. If no, go to step  9.
  5. 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 Wide Open Throttle (WOT) in park or neutral. Does the vacuum measure less than 5 in. Hg through the entire RPM range? If yes, go to next step. If no, go to step  10.
  6. Start and idle the engine until the idle speed drops to 680 RPM. Command the fuel pressure control to 160 MPa with a scan tool. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Is the Actual Fuel Rail Pressure parameter more than 145 MPa? If yes, go to next step. 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.
    7. NOTE: If the fuel temperature is near 250°F (121°C) during the duplication of the complaint (or in the Failure Records for this DTC), check for a restriction in the fuel cooler air flow or the fuel heater always ON. See FUEL HEATER ALWAYS ON in appropriate SYSTEM & COMPONENT TESTING article.
  7. Ensure that the J 44638 Vacuum gauge is still installed on the engine. Operate the vehicle within the conditions for which the customer complaint occurs. Does the vacuum measure less than 12 in. Hg through the entire operating range? If yes, go to next step. If no, go to step  10.
  8. Ask the customer if there has been a power-enhancing device attached to the fuel rail pressure sensor circuits. What was the customers answer? If yes, go to step  16. 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.
  9. Disconnect the fuel rail pressure sensor. Observe the Actual Fuel Rail Pressure with a scan tool. Does the Actual Fuel Rail Pressure measure more than 175 MPa? If yes, go to step  14. If no, go to step  13.
  10. Replace the fuel filter. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
  11. Ensure that the J 44638 Vacuum gauge is still installed on the engine. Start and run the engine under the conditions for which the high vacuum occurred in the previous test. Observe the J 44638. Does the vacuum measure less than or equal to 5 in. Hg at idle or 12 in. Hg at high speed? If yes, go to step  16. If no, go to next step.
  12. Repair the restriction in the fuel supply lines between the fuel tank and the fuel injection pump. After repairs, go to step  16.
  13. Check the fuel rail pressure sensor signal circuit for a short to ground. Repair as necessary. Did you find and correct the condition? If yes, go to step  16. If no, go to step  15.
  14. Replace the fuel rail pressure sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  16.
  15. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See ENGINE CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  16. 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.
  17. 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.
scientia non olet · About LEMON Manuals