LEMON Manuals: Even more car manuals for everyone
Home >> Isuzu >> 1996 >> Trooper SE >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0502 - Vehicle Speed Sensor (VSS) Circuit/Low Input

DTC P0502 - Vehicle Speed Sensor (VSS) Circuit/Low Input

  1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. Check speedometer. If speedometer works, go to step 11). If speedometer does not work, go to next step.
  3. Disconnect VSS harness connector and turn ignition on (with engine off). Connect a test light to positive battery terminal. Probe VSS connector ground terminal. If test light illuminates, go to step 5). If test light does not illuminate, go to next step.
  4. Repair sensor ground. Retest system.
  5. With sensor disconnected, turn ignition on. Using DVOM, probe VSS connectors ground and voltage supply. If battery voltage is not displayed on DVOM, go to next step. If battery voltage is displayed, go to step 7).
  6. Repair open or short to ground which may have blown meter fuse. Retest system.
  7. With sensor disconnected, turn ignition on. Using DVOM, measure voltage between VSS connector ground and speedometer wire. If DVOM reads 7.5-8.0 volts, go to step 9). If reading is not as specified, go to next step.
  8. Repair open or short circuit between speedometer and VSS. Retest system.
  9. Raise and support rear of vehicle. Reconnect VSS harness connector. Using DVOM, backprobe between ground and terminal containing wire from speedometer. Turn ignition on, with engine off and place transmission in Neutral. Rotating rear wheels by hand, observe DVOM readings. If reading toggles between .6 volt and 10 volts, go tostep 11). If readings are not as specified, go to next step.
  10. Replace VSS. Retest system.
  11. With vehicle still in Neutral, suspended above ground and ignition on, use scan tool to monitor VSS data while turning rear wheels by hand. If scan tool reads vehicle speed (about one MPH), go tostep 13). If scan tool does not read vehicle speed, go to next step.
  12. Repair open or short between PCM and speedometer, speedometer ground, faulty meter circuit board or faulty speedometer. Retest system.
  13. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Using DVOM, backprobe PCM connector. If DVOM reads near 9.4 volts, go to step 15). If voltage is not as specified, go to next step.
  14. Check for poor PCM harness connection or damaged terminal. Repair as necessary. Retest system.
  15. Replace PCM. Retest system.
scientia non olet · About LEMON Manuals