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Home › Chevrolet › 2001 › Tracker 2D Utility, RWD, Automatic › Repair and Diagnosis › Engine Performance › System › Engine Control System Self-Diagnostics › Diagnostic Tests › DTC P0451: Fuel Tank Pressure Sensor Performance - With ORVR › Diagnostic Procedures

Diagnostic Procedures

  1. Perform diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
  2. Turn ignition off. Remove fuel filler cap. Turn ignition on, with engine off. Using scan tool, select FTP sensor parameter. If pressure is within 0.0-0.5 in. H2O (0.0-0.9 mm Hg), go to step  11 . If pressure is not within 0.0-0.5 in. H2O (0.0-0.9 mm Hg), go to next step.
  3. Turn ignition off. Remove fuel tank. Remove FTP sensor from fuel tank. Check sensor air vent hole and air pressure inlet passage for clogging. If any problem is found, go to step  13 . If no problem is found, go to next step.
  4. Disconnect FTP sensor harness connector. Turn ignition on, with engine off. Using a DVOM, check voltage on FTP sensor harness connector terminal No. 3 (Gray/Red wire). If voltage reading is 5 volts, go to step  6 . If voltage reading is not 5 volts, go to next step.
  5. Turn ignition off. Check for open in Gray/Red wire between FTP sensor and PCM. Repair as necessary. After repairs, go to step  18 . If circuit is okay, go to step  14 .
  6. Using a test light connected to battery voltage, probe FTP sensor harness connector terminal No. 2 (Gray/Yellow wire). If test light illuminates, go to step  8 . If test light does not illuminate, go to next step.
  7. Turn ignition off. Check for open in Gray/Yellow wire between FTP sensor and PCM. Repair as necessary. After repairs, go to step  18 . If circuit is okay, go to step  14 .
  8. Reconnect FTP sensor harness connector. Using a DVOM connected to ground, backprobe FTP sensor harness connector terminal No. 1 (Brown/Red wire). If voltage reading is 2.5-2.7 volts, go to next step. If voltage reading is not 2.5-2.7 volts, go to step  15 .
  9. Apply a small amount of vacuum to FTP sensor while observing DVOM. If voltage decreases when vacuum is applied, go to next step. If voltage does not decrease when vacuum is applied, go to step  16 .
  10. Check for open in Brown/Red wire between sensor and PCM. Repair as necessary. After repairs, go to step  18 . If circuit is okay, go to step  14 .
    11. CAUTION: DO NOT breathe air through EVAP component tubes or hoses. Fuel vapors inside EVAP components may cause personal injury.
  11. Remove FTP control valve. Connect a vacuum hose to canister side port of FTP control valve. Blow air into hose on FTP control valve (some resistance should be present). If air flows through the valve to the tank port side, go to next step. If does not flow through the valve to the tank port side, go to step  17 .
    12. NOTE: FTP control valve allows vapor to flow from fuel tank to the canister when fuel tank pressure is greater than canister pressure by more than 0.5 psi (3.5 kPa).
  12. Connect a hose to fuel tank port of FTP control valve. From the tank side port, blow hard through the valve. Air should flow through the valve out of the canister port. If FTP control valve passes this test, see DIAGNOSTIC AIDS  . If FTP control valve does not pass this test, go to step  17 .
  13. Clean sensor orifice. After cleaning orifice, go to step  18 .
  14. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to step  18 .
  15. Turn ignition off. Check for short in Brown/Red wire between FTP sensor and PCM. Repair as necessary. After repairs, go to step  18 . If circuit is okay, go to next step.
  16. Turn ignition off. Replace FTP sensor. After replacing sensor, go to step  18 .
  17. Turn ignition off. Replace FTP control valve. After replacing control valve, go to next step.
  18. Clear DTCs. On 2.0L, turn ignition off. Remove DOME fuse for 30 seconds. Reinstall fuse. Reset radio clock time. On 2.5L, turn ignition on with engine off. Use scan tool to clear DTCs. Turn ignition off for 30 seconds. On all models, start engine and operate vehicle within the conditions for running the DTC or until DTC P0451 diagnostic test has run. See CODE ENABLE CRITERIA  . If DTC runs and passes, go to next step. If DTC resets, go to step  2 .
  19. Using scan tool, observe stored information and Capture Info. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no other DTCs are displayed, system is okay.
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