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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 voltage circuit (Gray wire) at fuel tank pressure sensor 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 8). If open exists, go to step 12).
  5. Remove fuel filler 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 13).
  6. Check fuel tank pressure sensor signal circuit (Dark Green wire) for poor connection at PCM. If poor connection does not exist, go to next step. If poor connection exists, go to step 11).
  7. Check fuel tank pressure sensor signal circuit (Dark Green wire) for open and short between PCM and fuel tank pressure harness connectors. If open or short exists, go to step 12). If open or short does not exist, go to step 14).
  8. 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 11).
  9. 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 12). If open does not exist, go to step 14).
  10. Check for poor connection at fuel tank pressure sensor. If poor connection exists, go to next step. If poor connection does not exist, go to step 13).
  11. Repair poor connections as necessary and go to step 15).
  12. Repair open or short as necessary and go to step 15).
  13. Replace fuel tank pressure sensor and go to step 15).
  14. Replace PCM and go to next step.
  15. Turn ignition switch to LOCK position. Remove gas cap. Connect scan tool to data link connector. Turn ignition switch to RUN position. Observe fuel tank pressure on scan tool. If zero in. H2O is displayed, go to next step. If zero in. H2O is not displayed, go to step 2).
  16. Replace gas cap. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Using scan tool, command EVAP canister vent valve on. Using diagnostic station, pressurize EVAP system to 5 in. H2O. Observe fuel tank pressure on scan tool. If 5 in. H2O is displayed, system is okay at this time. If 5 in. H2O is not displayed, go to step 2).
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