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Home >> Oldsmobile >> 2003 >> Bravada AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 4.2L >> Diagnostic Tests >> DTC P0452: EVAP System Pressure Sensor - Low Input >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. With scan tool, observe the Fuel Tank Pressure (FTP) sensor voltage. Does scan tool indicate that the FTP sensor voltage is less than 0.1 volt? If yes, go to step  4. If no, go to next step.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the Conditions For Running DTC or as close to the Freeze Frame/Failure Records data that you observed. See CONDITIONS FOR RUNNING DTC . Does the DTC fail this ignition cycle? If yes, go to next step. If no, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article.
  4. Turn ignition on, with engine off. Disconnect the FTP sensor. Measure the voltage from the 5-volt reference circuit of the FTP sensor to a good ground with a DVOM. Is the voltage within 4.8-5.2 volts? If yes, go to step  6. If no, go to next step.
  5. Disconnect the following components, while monitoring the DVOM: MAP sensor, TP sensor and A/C pressure sensor. Is DVOM reading within 4.8-5.2 volts when any of the components are disconnected? If yes, go to step  11. If no, go to step  7.
  6. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the FTP sensor and the signal circuit of the FTP sensor. Observe the Fuel Tank Pressure Sensor parameter with a scan tool. Is Fuel Tank Pressure Sensor parameter within 4.8-5.2 volts? If yes, go to step  9. If no, go to step  8.
  7. Test the FTP 5-volt reference circuit for an open or for a short to ground. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  8. Test the FTP sensor signal circuit for an open or for a short to ground. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  9. Test for an intermittent and for a poor connection at the FTP sensor. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  10. Test for an intermittent and for a poor connection at the control module. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  11. Replace the component that affected the 5-volt reference circuit. After replacing component(s), go to step  14.
  12. Replace FTP sensor. See REMOVAL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article. After replacing sensor, go to step  14.
  13. Replace PCM. See REMOVAL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  14. Clear the DTCs with scan tool. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the Conditions For Running DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. Observe the stored information, Capture Info with scan tool. Does scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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