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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. Inspect the fuel cooler located in front of the fuel tank for debris restricting the airflow or damage to the cooling fins. Inspect the fuel lines for kinks or damage. Clean or replace the above listed components as necessary. Did any of the components require a repair? If yes, go to step  11. If no, go to next step.
  3. Disconnect the air filter outlet duct to access the FRT sensor. Disconnect the FRT electrical connector. Turn ON the ignition. Probe the FRT sensor signal circuit with a Digital Multimeter (DMM) connected to ground. Is the voltage near 5 V? If yes, go to next step. If no, go to step  5.
  4. Connect a test lamp to battery voltage. Probe the low reference circuit of the FRT sensor connector. Does the test lamp illuminate? If yes, go to step  7. If no, go to step  6.
  5. Turn OFF the ignition. Disconnect the ECM connector that contains the FRT sensor signal circuit. Inspect the signal circuit for an open or short to voltage or ground and repair the circuit as necessary. Did you find and correct the condition? If yes, go to step  11. If no, go to step  8.
  6. Turn OFF the ignition. Disconnect the ECM connector that contains the fuel temperature sensor low reference circuit. Inspect the FRT sensor low reference circuit and connectors for an open or high resistance and repair the circuit. Did you complete the repair? If yes, go to step  11. If no, go to step  8.
  7. Inspect for poor connections at the FRT sensor and repair as necessary. Did you find and correct the condition? If yes, go to step  11. If no, go to step  9.
  8. Inspect for poor connections at the ECM and repair as necessary. Did you find and correct the condition? If yes, go to step  11. If no, go to step  10.
  9. Replace the FRT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  11.
  10. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See ENGINE CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  11. 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.
  12. 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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