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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 429 (Engine Controls Self-Diagnostics - 6.0L Bi-Fuel & CNG) >> Diagnostic Tests >> DTC P1433: Fuel Pressure Sensor Signal High >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 GMC Savana and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Alternative Fuels - Engine Controls. If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ALTERNATIVE FUELS - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn ignition on, with engine off. Observe the Fuel Tank Pressure (FTP) data parameter using a scan tool. If the scan tool displays a FTP sensor voltage of more than 4.75 volts, go to step  4. If the scan tool displays a FTP sensor voltage of less than 4.75 volts, go to next step.
  3. Observe the Freeze Frame and/or the Failure records data for this DTC. Turn the ignition off for 30 seconds. Start the engine. Operate the vehicle within the Conditions For Running The DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure records data. If the DTC failed this ignition cycle, go to next step. If the DTC did not fail this ignition cycle, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Using a scan tool, observe the Fuel Tank Temperature (FTT) sensor data parameter. If the scan tool displays a FTT sensor voltage of more 4.75 volts, go to step  12. If the scan tool displays a FTT sensor voltage of less than 4.75 volts, go to next step.
    5. NOTE: If the jumper fuse opens, repair the signal circuit short to battery voltage.
  5. Remove the fuel tank cover. Disconnect the FTP sensor harness connector. Connect a 3-amp fused jumper wire between the FTP sensor signal circuit and a good ground. Using a scan tool, observe the FTP sensor data parameter. If the scan tool displays a FTP sensor voltage of less than 0.25 volts, go to next step. If the scan tool displays a FTP sensor voltage of more than 0.25 volts, go to step  8.
  6. Remove the jumper. Measure the voltage from the 5-volt reference circuit of the FTP sensor with a DVOM. If the DVOM display a voltage of more than 5.2 volts, go to step. If the DVOM displays a voltage of less than 5.2 volts, go to next step.
  7. Probe the FTP sensor ground circuit with a test light connected to battery positive. If the test light illuminates, go to step  10. If the test light does not illuminate, go to step  13.
  8. Test the FTP sensor signal circuit for a short to voltage or an open. Did you find and correct the a short to voltage or an open? If yes, go to step  16. If no, go to step  11.
  9. Test the FTP sensor 5-volt reference circuit for a short to voltage. Did you find and correct a short to voltage? If yes, go to step  16. If no, go to step  15.
  10. Test for an intermittent and/or a poor connection at the FTP sensor. Did you find and correct an intermittent and/or a poor connection? If yes, go to step  16. If no, go to step  14.
  11. Test for an intermittent and/or a poor connection at the PCM. Did you find and correct an intermittent and/or a poor connection? If yes, go to step  16. If no, go to step  15.
  12. Repair the FTP sensor ground circuit for an open between the ground terminal and the splice. After repair is complete, go to step  16.
  13. Repair the FTP sensor ground circuit for an open, or high resistance, between the FTP sensor harness connector and the splice. After repair is complete, go to step  16.
  14. Replace the FTP sensor. After replacement is complete, go to next step.
  15. Replace the PCM. After replacement is complete, go to next step.
  16. Using a scan tool, clear the DTCs. Turn ignition off for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. If the DTC failed this ignition cycle, go to step  2. If the DTC did not fail this ignition cycle, go to next step.
  17. Observe the Capture Info using a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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