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Fuel Tank Pressure Sensor Diagnosis

  1. If powertrain OBD system check has been performed, go to next step. If powertrain OBD system check has not been performed, perform powertrain OBD system check. See POWERTRAIN OBD SYSTEM CHECK in TESTS W/CODES article.
  2. Disconnect fuel tank pressure sensor harness connector. Measure voltage at reference signal circuit (Gray wire) at fuel tank pressure harness connector. If about 5 volts does not exist, go to next step. If about 5 volts exists, go to step 5).
  3. Check for poor connection at PCM. If poor connection does not exist, go to next step. If poor connection exists, go to step 12).
  4. Check fuel tank pressure sensor reference voltage circuit (Gray wire) for open between PCM and fuel tank pressure sensor harness connector. If open does not exist, go to step 9). If open exists, go to step 11).
  5. Remove gas cap. Using 2 fused jumper wires, connect reference voltage and signal circuits between fuel tank sensor and fuel tank pressure sensor harness connector. Measure voltage at ground terminal at fuel tank pressure sensor. If 1.3-1.7 volts exist, go to next step. If 1.3-1.7 volts do not exist, go to step 14).
  6. Check fuel tank pressure sensor signal circuit (Dark Blue wire) for poor connection at PCM. If poor connection does not exist, go to next step. If poor connection exist gas cap. Using 2 fused jumper wires, connect reference voltage and signal circuits between fuel tank sensor and fuel tank pressure sensor harness connector. Measure voltage at ground terminal at fuel tank pressure sensor. If 1.3-1.7 volts exists, go to next step. If 1.3-1.7 volts does not exist, go to step 14).
  7. Check fuel tank pressure sensor signal circuit (Dark Blue wire) for poor connection at PCM. If poor connection does not exist, go to next step. If poor connection exists, go to step 12).
  8. Check fuel tank pressure sensor signal circuit (Dark Blue wire) for open and short between PCM and fuel tank pressure harness connectors. If open or short exists, go to step 13). If open or short does not exist, go to step 15).
  9. Check fuel tank pressure sensor ground circuit (Black wire) for poor connection at PCM. If poor connection does not exist, go to next step. If poor connection exists, go to step 12).
  10. Check fuel tank pressure sensor ground circuit (Black wire) for open between PCM and fuel tank pressure harness connectors. If open exists, go to step 13). If open does not exist, go to step 15).
  11. Repair open in fuel tank pressure sensor reference voltage circuit (Gray wire), between PCM and fuel tank pressure sensor harness connectors. After repair are complete, perform EVAP CONTROL SYSTEM DIAGNOSIS.
  12. Repair connections as necessary and perform EVAP CONTROL SYSTEM DIAGNOSIS.
  13. Repair open or short as necessary and perform EVAP CONTROL SYSTEM DIAGNOSIS.
  14. Replace fuel tank pressure sensor and perform EVAP CONTROL SYSTEM DIAGNOSIS.
  15. Replace PCM. Program PCM, perform VTD password relearn procedure and perform crankshaft variation learn procedure. See COMPUTER RELEARN PROCEDURES in GENERAL INFORMATION.
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