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Home >> Isuzu >> 2003 >> Rodeo S, 2.2 D, Standard >> 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 harness connector. VSS is located in transmission tail shaft 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 VSS ground (Black wire) between ground point C-16 and VSS. Ground point C-16 is located on left fender well. After repairs are 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 VSS voltage supply (Yellow wire) between CB-11 METER (15-amp) fuse and VSS. After repairs are complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  6. Turn ignition off. Disconnect PCM White harness connector C-2. Check for open or short to ground in VSS input (Black/Yellow wire) between PCM and VSS. See Fig 1 . If problem is found, repair as necessary. After repairs are 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 appropriate REMOVAL & INSTALLATION article. After repairs are complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  10. Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE REPLACEMENT  under POWERTRAIN CONTROL MODULE. After repairs are 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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