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Testing Procedure

WARNING: This page is about a different car, the 2002 Isuzu Trooper, 2002 Isuzu Rodeo Sport, 2002 Isuzu Rodeo, 2002 Isuzu Axiom, and 2002 Honda Passport. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - TROOPER 3.5L article. After performing OBD-II system check, go to next step.
  2. Check C-9 IG. COIL (15-amp) and C-8 ENGINE (15-amp) fuse located in dashboard fuse box. Check FL-3 ECM (30-amp) fuse located in underhood fuse/relay box. If any fuse is blown, go to next step. If fuses are okay, go to step  4 .
  3. Check for short to ground in ignition feed circuit between suspect fuse and ION sensing module or PCM. See WIRING DIAGRAMS article. If problem is found, repair as necessary. Replace any blown fuses. After repair, test drive vehicle to confirm repair.
  4. Turn ignition off. Install fuel pressure gauge to fuel supply line test fitting. Turn ignition on. Fuel pressure should be 42-55 psi (283-376 kPa) and hold steady for 2 seconds. If fuel pressure is as specified, leave fuel pressure gauge connected and go to step  6 . If fuel pressure is not as specified, go to next step.
  5. If no fuel pressure is indicated, go to FUEL SYSTEM DIAGNOSIS  under FUEL SYSTEM. If any fuel pressure is indicated, go to FUEL SYSTEM ELECTRICAL TEST  under FUEL SYSTEM.
  6. Install Injector Tester (J-39021) and switch box at injector test connector Gray 7-pin in-line harness connector. In-line harness connector is bolted to front of right valve cover, below where air duct attaches to MAF sensor. While observing fuel pressure gauge activate fuel injector. If fuel pressure drops, go to next step. If fuel pressure does not drop, go to  18 .
  7. Install fuel injector test light (noid light) at cylinder No. 2 injector harness connector. Crank engine. If noid light blinks, go to next step. If noid light does not blink, go to step  24 .
    8. WARNING: Use gray narrow Metripak flexible female connector from J-35616 Connector Test Adaptor kit (or equivalent) to access terminals and prevent terminal and connector damage.
  8. Turn ignition off. Disconnect ION sensing 11-pin harness connector. ION sensor is located on top of intake manifold. Using a test light connected to battery voltage, probe each of the 6 exposed pins while cranking engine. If test light flashes at each pin, connect disconnected harness connectors and go to step  12 . If test light does not flash at each pin, go to next step.
  9. Turn ignition off. Disconnect ION sensing module 4-pin harness connector. Turn ignition on. Using a test light connected to ground, probe ION sensing module harness connector E-16 terminal No. 7 (Black/Orange wire). See WIRING DIAGRAMS article. Connect test light to battery voltage, probe ION sensing module harness connector E-16 terminal No. 1 (Black wire). If test light does not illuminate at both terminals, go to next step. If test light illuminates at both terminals, go to step  11 .
  10. Repair open in Black/Orange wire (ION sensing module ignition feed) between ISM and C-9 IG. COIL fuse, or in Black wire (ION sensing module ground) between ground point E-29 and ISM. Ground point is forward of 2 grounds located on right side of intake manifold. After repair, test drive vehicle to confirm repair.
  11. Replace ION sensing module. After repair, test drive vehicle to confirm repair.
  12. Disconnect 3-pin harness connector from each ignition coil. Using a test light connected to battery voltage, probe each ignition coil harness connector terminal No. 1. See IDENTIFYING IGNITION COIL TO ISM WIRES  table. While cranking engine, observe test light. If test light flashes at each ignition coil, leave harness connectors disconnected and go to step  14 . If test light does not flash at each ignition coil, go to next step.
    IDENTIFYING IGNITION COIL TO ISM WIRES

    Ignition Coil/Cylinder No. (1) Wire Color
    1 Red
    2 Red/Black
    3 Red/Blue
    4 Red/White
    5 Red/Yellow
    6 Red/Green
    (1) Test each ignition coil at harness connector terminal No. 1.
  13. Check for and repair open in circuits between suspect ignition coil and ION sensing module. See WIRING DIAGRAMS article. If problem is found, repair as necessary. After repair, test drive vehicle to confirm repair.
  14. Turn ignition on. Using a test light connected to ground, probe Black/Orange wire (ignition feed circuit) at each ignition coil harness connector. If test light illuminates at each terminal, leave harness connectors disconnected and go to step  16 . If test light does not illuminate at each terminal, go to next step.
  15. Repair open in Black/Orange wire (ignition feed circuit) between suspect ignition coil and C-9 IG. COIL fuse. After repair, test drive vehicle to confirm repair.
  16. Using a test light connected to battery voltage, probe secondary ground circuit of each ignition coil at harness connector (Black wire). If test light does not illuminate at each terminal, go to next step. If test light does illuminate at each terminal, go to step  18 .
  17. Repair open circuit in Black wire between appropriate ignition coil and ground. After repair, test drive vehicle to confirm repair.
  18. Test for fuel contamination. If fuel is contaminated, clean fuel system as necessary. Replace fuel filter and verify all fuel injectors are delivering fuel. After repair, test drive vehicle to confirm repair. If fuel is not contaminated, go to next step.
  19. Remove any ignition coil. Install spark tester at spark plug end of coil. While cranking engine, check ignition coil for crisp, Blue spark. If weak spark or no spark is present, go to next step. If spark is okay, go to step  21 .
  20. Replace faulty ignition coil. Repeat test from previous step for each ignition coil. If problem is found, replace coil(s) as necessary. After repair, test drive vehicle to confirm repair.
  21. Repeat test from step  19 for each ignition coil. Test one coil at a time, and reinstall each coil on its spark plug when testing is complete (DO NOT install screws). Attempt to start engine. If engine does not start, go to next step. If engine starts, install ignition coil screws and test drive vehicle to confirm repair.
  22. Remove all spark plugs. Inspect spark plugs for fouling, loose or missing electrodes, or cracked insulators. Clean or replace spark plugs as necessary. If spark plugs are okay, go to next step.
  23. Check for these possible conditions:
    • Faulty or incorrect camshaft timing belt.
    • Leaking or sticking valves or rings.
    • Excessive valve deposits.
    • Loose or worn rocker arms.
    • Weak valve springs.
    • Incorrect valve timing.
    • Leaking head gasket.

    If problem is found, repair as necessary. See appropriate article in ENGINES. If no problem is found, go to step  25 .

    24. NOTE: If scan tool is powered by cigarette lighter socket and display goes blank while cranking engine, it will be necessary to power scan tool directly from battery.
  24. Using scan tool, select ENGINE SPEED parameter. While cranking engine, observe scan tool. If RPM is indicated on scan tool, go to next step. If engine RPM is not indicated, go to step  34 .
  25. Turn ignition off. Disconnect fuel injector tester Gray 7-pin in-line harness connector. In-line harness connector is bolted to front of right valve cover, below where air duct attaches to MAF sensor. Turn ignition on. Using a test light connected to ground, on female side of connector probe fuel injector tester in-line harness connector terminal No. 1 (Red/Blue wire). See Figure . If test light illuminates, go to next step. If test light does not illuminate, go to step  32 .
  26. Connect test light between female side of fuel injector tester in-line harness connector terminals No. 1 (Red/Blue wire) and specified terminal. See IDENTIFYING FUEL INJECTOR TESTER IN-LINE HARNESS CONNECTOR TERMINALS  table. See Figure . Turn ignition on. If test light illuminates and stays on at any terminal, leave test light connected and go to next step. If test light does not illuminate and stay on at any terminal, go to step  29 .
    IDENTIFYING FUEL INJECTOR TESTER IN-LINE HARNESS CONNECTOR TERMINALS

    Application Wire Color
    Injector No. 1 Green/White
    Injector No. 2 Green/Orange
    Injector No. 3 Green
    Injector No. 4 Green/Red
    Injector No. 5 Green/Black
    Injector No. 6 Green/Yellow
  27. Turn ignition off. Disconnect PCM 80-pin harness connector E-22. PCM is located on fenderwell at right side of engine compartment. Turn ignition on. If test light illuminates, go to next step. If test light does not illuminate, go to step  33 .
  28. Repair short to ground in suspect fuel injector driver circuit. See WIRING DIAGRAMS article. After repair, test drive vehicle to confirm repair.
  29. Connect test light between female side of fuel injector tester in-line harness connector terminals No. 1 (Red/Blue wire) and specified terminal. See IDENTIFYING FUEL INJECTOR TESTER IN-LINE HARNESS CONNECTOR TERMINALS  table. See Figure . Observe test light while cranking engine. If test light flashes at any terminal, leave harness connector disconnected and go to step  31 . If test light does not flash at any terminal, go to next step.
  30. Check for open in suspect injector driver circuit. See WIRING DIAGRAMS article. If problem is found, repair as necessary. After repair, test drive vehicle to confirm repair. If no problem was found, go to step  33 .
  31. Turn ignition off. Using DVOM, measure resistance between male side of fuel injector tester Gray 7-pin in-line harness connector terminals No. 1 and specified terminal. See IDENTIFYING FUEL INJECTOR TESTER IN-LINE HARNESS CONNECTOR TERMINALS  table. See Figure . Resistance should be about 12.5 ohms at all pins. If resistance is as specified, repeat test starting in step  8 . If resistance is not as specified at all pins, check for an open, shorted or faulty fuel injector. Repair or replace fuel injector(s) as necessary. After repair, test drive vehicle to confirm repair.
  32. Repair open in Black/Orange wire (ignition feed) between CB-13 IG. COIL fuse and PCM. See WIRING DIAGRAMS article. After repair, test drive vehicle to confirm repair.
  33. Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE REPLACEMENT under POWERTRAIN CONTROL MODULE in SELF-DIAGNOSTICS - TROOPER 3.5L article. After repair, test drive vehicle to confirm repair.
  34. Turn ignition off. Raise and support vehicle. Disconnect Crankshaft Position (CKP) sensor 3-pin harness connector. Turn ignition on. Using a test light connected to ground, probe CKP sensor harness connector terminal No. 1 (Blue wire). If test light does illuminate, leave harness connector and go to step  36 . If test light does not illuminate, go to next step.
  35. Check for and repair open or short to ground in Blue wire (ignition feed) between CKP sensor and PCM. See WIRING DIAGRAMS article. After repair, test drive vehicle to confirm repair.
  36. Turn ignition on. Connect a test light between CKP sensor harness connector terminals No. 1 (Blue wire) and No. 2 (Green wire). If test light illuminates, go to step  38 . If test light does not illuminate, go to next step.
  37. Check for and repair open or short to voltage in Green wire (CKP ground) between CKP sensor and PCM. See WIRING DIAGRAMS article. After repair, test drive vehicle to confirm repair.
  38. Check for open, short to ground or short to voltage in Yellow/Red wire (CKP signal circuit) between CKP sensor and PCM. If problem is found, repair as necessary. After repair, test drive vehicle to confirm repair. If no problem is found, go to next step.
  39. Replace CKP sensor. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. After repair, test drive vehicle to confirm repair. If system is still not operating properly, repeat test starting in step  33 .
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