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Home >> Isuzu >> 1998 >> Trooper LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Introduction >> On-Board Diagnostic II (OBD-II) System Check >> Hombre 4.3L
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Hombre 4.3L

NOTE: Powertrain Control Module (PCM) may also be referred to as VCM.
NOTE: Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm impedance, unless stated otherwise in test procedure.
  1. Turn ignition off. Install Tech 2 scan tool and follow scan tool manufacturer's instructions to proceed with test. Turn ignition on. If scan tool displays VCM data, go to next step. If scan tool does not display VCM data, go to BASIC TESTING article.
  2. Turn ignition on with engine off. Observe Malfunction Indicator Light (MIL). If MIL illuminates, go to next step. If MIL does not illuminate, go to MALFUNCTION INDICATOR LIGHT (MIL) INOPERATIVE.
  3. Using scan tool, select DIAGNOSTIC SYSTEM CHECK. Monitor SERIAL DATA CLASS II messages. If all modules connected to Serial Data Class II circuits are communicating, go to next step. If any module(s) is not communicating, recheck all harness connections and scan tool installation. Repair as necessary.
  4. Using scan tool, check for any class II DTCs. If no DTCs are stored, go to next step. If any DTCs are stored, go to DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION . Proceed to appropriate DTC test under DIAGNOSTIC TESTS in appropriate TESTS W/CODES articles below:
  5. Using scan tool, command MIL to turn off. If MIL turns off, go to next step. If MIL does not turn off, see BASIC TESTING article.
  6. Crank engine for 10 seconds. If engine starts, go to next step. If engine does not start, see BASIC TESTING article.
  7. Using scan tool, retrieve any stored DTCs. If DTC P1626 or P1631 is retrieved, see appropriate DTC test under DIAGNOSTIC TESTS in appropriate TESTS W/CODES articles below:

    If indicated DTCs are not stored, see BASIC TESTING article.

  8. Using scan tool, observe DTC status for MIL REQUEST, FAIL THIS IGN, LAST TST FAIL and HISTORY. If any DTC(s) is stored, save freeze frame and fail record information using scan tool CAPTURE INFO feature. If any of these DTC status are present, refer to affected DTC to diagnose problem. If DTC(s) are not present, go to next step.
  9. Turn ignition on with engine off. Using scan tool, check Engine Coolant Temperature (ECT) sensor values. Start engine and warm to normal operating temperature. Compare readings with scan tool data list. If value is within typical range, go to next step. If value is not within limits, go to SYSTEM & COMPONENT TESTS article.
  10. If there is still a driveability complaint, see TESTS W/O CODES article. If no driveability problem exists, system is functioning properly.