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Home >> Isuzu >> 2002 >> Rodeo Sport 2.2 D, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Tests >> DTC P0502: Vehicle Speed Sensor Circuit - Low Input >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. Turn ignition off. Disconnect VSS 3-pin harness connector. VSS is located in transmission tailshaft housing. Using test light connected to battery voltage, probe VSS harness connector terminal No. 2 (Black wire). See Fig 1 . If test light illuminates, leave harness connector disconnected and go to step  4 . If test light does not illuminate, go to next step.
  3. Repair open in Black wire (VSS ground) between ground point C-16 and VSS. Ground point C-16 is located on left fender well. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition on. Measure voltage between ground and VSS harness connector terminal No. 1 (Yellow wire). See Fig 1 . If battery voltage exists, go to step  6 . If battery voltage does not exist, go to next step.
  5. Repair open or short to ground in Yellow wire (VSS voltage supply) between CB-11 METER (15-amp) fuse and VSS. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  6. Turn ignition off. Disconnect PCM White 32-pin harness connector C-2. PCM is located under center console in front of shifter. Check for open or short to ground in Black/Yellow wire (VSS input) between PCM and VSS. See Fig 1 . If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to step  9 .
  7. Measure resistance between VSS sensor body and transmission case. If resistance is 10 k/ohms or more, go to next step. If resistance is not as specified, go to step  9 .
  8. Remove VSS from transmission. Visually inspect VSS for damage. If problem is found, go to next step. If no problem is found, go to step  10 .
  9. Replace VSS. See ENGINE SWITCHES & SENSORS in REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  10. Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE REPLACEMENT  under POWERTRAIN CONTROL MODULE. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
Fig 1: Identifying Vehicle Speed Sensor Circuit
G00049063Courtesy of ISUZU MOTOR CO.
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