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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 155 (Engine Controls Self-Diagnostics - 5.7L - Bi-Fuel) >> Diagnostic Tests >> DTC P1433: Fuel Pressure Sensor Signal High >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Turn ignition on, with engine off. Using scan tool, establish communication with the AF ECM. Locate and observe the Fuel Tank Pressure (FTP) sensor data parameter. Does the FTP sensor indicate voltage greater than 4.7 volts? If yes, go to step  4 . If no, go to next step.
  3. The fault is not present. See DIAGNOSTIC AIDS  . Are any DTCs stored that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Locate and observe the Fuel Tank Temperature (FTT) sensor data parameter. Does the FTT sensor indicate voltage greater than 4.7 volts? If yes, go to step  8 . If no, go to next step.
  5. Remove the fuel tank cover. Disconnect the FTP sensor connector. Connect a fused jumper between the FTP sensor signal circuit terminal and a known-good ground. If the jumper fuse opens, repair the signal circuit shorted to battery voltage. Observe the FTP sensor data parameter. Does the FTP sensor indicate voltage less than 0.25 volt? If yes, go to next step. If no, go to step  9 .
  6. Remove jumper. Connect test leads of Digital Multimeter (DMM) between the 5-volt reference circuit terminal and sensor ground circuit terminal. Measure voltage of the 5-volt reference circuit at FTP sensor connector. Is voltage greater than 5.2 volts? If yes, go to step  10 . If no, go to next step.
  7. Connect the Unpowered Test Lamp (J-34142-B) between the sensor ground circuit terminal and battery voltage. Is test lamp illuminated? If yes, go to step  12 . If no, go to step  11 .
  8. Inspect the sensor ground circuit for an open or high resistance condition between the AF ECM connector terminal and circuit splice. Inspect AF ECM connector and any in-line connectors, if applicable, for proper terminal contact. Repair wiring or terminals as necessary. Was a repair necessary? If yes, go to step  15 . If no, go to step  14 .
  9. Inspect FTP sensor signal circuit for an open or high resistance condition between the AF ECM connector terminal and the circuit splice. Inspect the AF ECM connector and any in-line connectors, if applicable, for proper terminal contact. Inspect for a shorted condition between the FTP sensor 5-volt reference circuit and the FTP sensor signal circuit. Repair wiring or terminals as necessary. Was a repair necessary? If yes, go to step  15 . If no, go to step  14 .
  10. Test the FTP sensor 5-volt reference circuit for a short to voltage. The FTP sensor 5-volt reference circuit is not shared with any other 5-volt reference component on the vehicle. Repair wiring as necessary. Was a repair necessary? If yes, go to step  15 . If no, go to step  14 .
  11. Repair the open or high resistance condition of the sensor ground circuit between the FTP sensor connector terminal and the circuit splice. After repairs, go to step  15 .
  12. Inspect the FTP sensor connector for proper terminal contact. Repair terminal contact as necessary. Was a repair necessary? If yes, go to step  15 . If no, go to next step.
  13. Replace FTP sensor. See FUEL TANK PRESSURE SENSOR under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - CHEVY EXPRESS & SAVANA - BI-FUEL. After repairs, go to step  15 .
  14. Replace AF ECM. See ALTERNATE FUEL ENGINE CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CHEVY EXPRESS & SAVANA - BI-FUEL. Program (flash) AF ECM with correct vehicle software and calibration. See ALTERNATE FUEL ENGINE CONTROL MODULE  under PROGRAMMING. After performing repairs and procedures, go to next step.
  15. Using scan tool, clear the DTC information from BOTH control modules. Operate the vehicle under the Conditions For Running DTC. Using the scan tool parameter DTC STATUS, ensure that this DTC runs. Did this DTC RUN and PASS? If yes, system is okay. If no, go to step  2 .
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