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DTC P0453: EVAP System Pressure Sensor High Input

  1. Perform basic diagnostic procedure. See BASIC DIAGNOSTIC PROCEDURE  . Turn ignition off. Remove and reinstall fuel filler cap. Turn ignition on. Observe fuel tank pressure sensor signal. If pressure is more than 0.83 in. Hg, go to step  12 . If pressure is not more than 0.83 in. Hg, go to next step.
  2. Turn ignition on. Using DVOM connected to ground, backprobe ECM connector B135 (28-pin connector) terminal No. 9. See Figure . If voltage is more than 4.5 volts, go to step  4 . If voltage is not more than 4.5 volts, go to next step.
  3. Measure voltage between ground and ECM connector B135 (28-pin connector) terminal No. 9 while wiggling harness and ECM connector. If voltage changes more than 4.5 volts while wiggling harness and ECM connector, check for poor terminal contact at ECM connector. If voltage does not change more than 4.5 volts while wiggling harness and ECM connector, replace ECM.
  4. Using DVOM connected to ground, backprobe ECM connector B135 (28-pin connector) terminal No. 15. If voltage is less than 0.2 volt, go to step  6 . If voltage is not less than 0.2 volt, go to next step.
  5. Using scan tool, observe fuel tank pressure while wiggling harness and ECM connector. If pressure changes more than -0.83 in. Hg while wiggling harness and ECM connector, check for poor terminal contact at ECM connector. If pressure does not change more than -0.83 in. Hg while wiggling harness and ECM connector, go to next step.
  6. Turn ignition off. Disconnect Gray 6-pin in-line connector located between rear wiring harness and fuel tank harness (under rear seat). Turn ignition on. Using DVOM connected to ground, measure voltage at ECM-side of Gray 6-pin in-line connector terminal No. 5. See Figure . If voltage is more than 4.5 volts, go to next step. If voltage is not more than 4.5 volts, locate and repair open circuit in wiring and check for poor terminal contact in connectors between ECM and Gray 6-pin in-line connector. See WIRING DIAGRAMS article.
  7. Turn ignition off. Disconnect ECM connector B135 (28-pin connector). Using an ohmmeter, measure resistance between ECM connector B135 (28-pin connector) terminal No. 15 and ECM-side of Gray 6-pin in-line connector terminal No. 4. If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, locate and repair open circuit in wiring and check for poor terminal contact in connectors between ECM and Gray 6-pin in-line connector.
  8. Measure resistance between ECM connector B135 (28-pin connector) terminal No. 9 and ECM-side of Gray 6-pin in-line connector terminal No. 5. If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, locate and repair short in wiring between ECM and Gray 6-pin in-line connector.
  9. Disconnect fuel tank pressure sensor connector. Measure resistance between fuel tank pressure sensor harness connector terminal No. 2 and fuel-tank side of Gray 6-pin in-line connector terminal No. 4. See Figure and Figure . If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, locate and repair open circuit in fuel tank harness.
  10. Measure resistance between fuel tank pressure sensor harness connector terminal No. 1 and fuel-tank side of Gray 6-pin in-line connector terminal No. 1. If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, locate and repair open circuit in fuel tank harness.
  11. Check for poor terminal contact at fuel tank pressure sensor connector. If terminal contact is okay, replace fuel tank pressure sensor.
  12. Turn ignition off. Disconnect fuel tank pressure sensor connector. Turn ignition on. Using scan tool, read fuel tank pressure. If pressure is more than .83 in. Hg, locate and repair short to voltage in wiring between ECM and fuel tank pressure sensor. If pressure is not more than .83 in. Hg, replace fuel tank pressure sensor. Clear memory and perform verification procedure. See CLEARING DIAGNOSTIC TROUBLE CODES  and VERIFICATION PROCEDURE  .
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