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Home >> Chevrolet >> 2003 >> Tracker 2D Utility, RWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 2.0L >> Diagnostic Tests >> DTC P0451: Fuel Tank Pressure Sensor Performance >> Diagnostic Procedures

Diagnostic Procedures

  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 off. Remove fuel filler cap. Turn ignition on, with engine off. Select the FTP sensor parameter on scan tool. Is pressure within 0.0-0.5 in. H2O (0.0-0.9 mm Hg)? If yes, go to step  11. If no, go to next step.
  3. Remove fuel tank. Remove FTP sensor from fuel tank. Visually inspect sensor orifice and air pressure inlet passage for clogging. Clean FTP sensor orifice and inlet passage as necessary. Did you find and correct a condition? If yes, go to step  15. If no, go to next step.
  4. Turn ignition off. Disconnect the FTP sensor electrical connector. Turn ignition on, with engine off. Measure voltage of the 5-volt reference circuit with a DVOM connected to ground. Is the voltage at 5.0 volts? If yes, go to step  6. If no, go to next step.
  5. Test for high resistance in the 5-volt reference circuit between the VTP sensor and PCM. Repair as necessary. Did you find and correct a condition? If yes, go to step  15. If no, go to step  12.
  6. Connect a test light between the ground circuit of the FTP sensor and battery voltage. Does the test light illuminate? If yes, go to step  8. If no, go to next step.
  7. Test for an open or high resistance in the FTP sensor ground circuit. Repair as necessary. Did you find and correct a condition? If yes, go to step  15. If no, go to step  12.
  8. Turn ignition off. Connect FTP sensor electrical connector. Backprobe the FTP sensor input circuit at the PCM with a DVOM connected to ground. Turn ignition on, with engine off. Measure voltage with DVOM set to DC scale. Is voltage within 2.5-2.7 volts? If yes, go to next step. If no, go to step  10.
  9. Apply a small amount of vacuum to the FTP sensor while observing the DVOM. Does voltage decrease when vacuum is applied? If yes, go to next step. If no, go to step  14.
  10. Test the FTP sensor input circuit for high resistance or short to voltage. Repair as necessary. Did you find and correct a condition? If yes, go to step  15. If no, go to step  14.
  11. Inspect the EVAP system for the following conditions: Test the FTP control valve for proper operation. Inspect for a stuck closed or blocked EVAP canister vent valve. Inspect the vapor lines and hoses between the EVAP canister and the fuel tank for restrictions or blockage. Repair or Replace component as necessary. Did you find and correct a condition? If yes, go to step  15. If no, go to DIAGNOSTIC AIDS .
  12. Inspect the PCM and the Manifold Absolute Pressure (MAP) sensor electrical connectors for faulty terminal contact. Repair as necessary. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  13. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  14. Replace FTP sensor. After repairs, go to next step.
  15. Turn ignition off. Remove DOME fuse (located in passenger compartment fuse block). Reinstall DOME fuse. Reset radio clock time. Start engine. Operate the vehicle within the Freeze Frame conditions that set the DTC or until the P0451 diagnostic test has run. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  16. With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? DIAGNOSTIC TROUBLE CODE DEFINITIONS 
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