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Home >> Pontiac >> 2001 >> Firebird Formula, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 5.7L >> Diagnostic Tests >> DTC P0500: Vehicle Speed Sensor (VSS) Circuit >> Diagnostic Procedures
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Diagnostic Procedures

  1. If powertrain diagnostic system check was performed, go to next step. If powertrain diagnostic system check was not performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under DIAGNOSTIC SYSTEM TESTS. After performing powertrain diagnostic system check, go to next step.
  2. Turn ignition off. Raise and support drive axle. Disable traction control (ASR/TCS) system if equipped. Start engine. With engine at idle, place transmission in gear. Using scan tool, monitor vehicle speed. If displayed vehicle speed is more than zero, see DIAGNOSTIC AIDS . If displayed vehicle speed is zero MPH, go to next step.
  3. Turn ignition off. Locate and disconnect VSS connector. See Figure. Connect Signal Generator Tester (J-33431-B) to VSS connector (harness side). Turn ignition on. Set tester to generate VSS signal. Using scan tool, monitor displayed vehicle speed. If displayed vehicle speed is more than zero MPH, go to next step. If displayed vehicle speed is zero MPH, go to step  5.
  4. Repair faulty VSS connection or replace faulty VSS. See REMOVAL, OVERHAUL & INSTALLATION - CARS article. After repairs, go to step  12.
  5. Disconnect signal generator. Ensure ignition is on. Using DVOM, measure voltage between ground and VSS connector terminal "B" (Purple/White wire). If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step  9.
  6. Using DVOM, measure voltage between VSS connector terminals "A" (Light Green/Black wire) and "B" (Purple/White wire). If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step  10.
  7. Check vehicle calibration code. If calibration is correct, go to next step. If calibration is incorrect, go to step  11.
  8. Replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - CARS article. After replacing PCM, go to step  12.
  9. Repair faulty Purple/White wire between VSS and PCM connector C2 terminal No. 21. See Figure. After repairs, go to step  12.
  10. Repair faulty Light Green/Black wire between VSS and PCM connector C2 terminal No. 20. See Figure. After repairs, go to step  12.
  11. Using scan tool, install proper or most current calibration code into PCM. After entering calibration code, go to next step.
  12. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step  2.
  13. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.
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