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Ignition System

  1. Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . After performing OBD system check, go to next step.
  2. Turn ignition on. Using scan tool, select FAILED SINCE CODE CLEAR function. If Diagnostic Trouble Code (DTC) P0123, P0506, P0507, P0601, P0602 or P1629 is present, diagnose applicable DTC. See the TESTS W/CODES article. If DTC is not present, go to next step.
  3. Check Ignition Control Module (ICM) ignition feed circuit fuse. If fuse is blown, locate and repair short to ground in ICM ignition feed circuit or short to voltage in IC circuit. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If fuse is okay, go to next step.
  4. Using scan tool, observe engine speed display while cranking engine. If RPM is indicated, go to next step. If RPM is not indicated, go to step 23).
  5. Turn ignition off. Disconnect injector connector. Install Injector Test Light (J-34730-2) to injector connector. See the WIRING DIAGRAMS article. Turn ignition on. If injector test lights illuminates, go to step 18). If injector test lights does not illuminate, go to next step.
  6. Crank engine and monitor injector test lights. If all injector test lights flash, go to next step. If any of injector test light does not flash, go to step 19).
  7. Turn ignition off. Install fuel pressure gauge to fuel injector test fitting. Turn ignition on and observe fuel pressure. Fuel pressure should be 48-55 psi (3.4-3.9 kg/cm2 ) and hold steady. If fuel pressure is as specified, go to step 9). If fuel pressure is not as specified, go to next step.
  8. If fuel pressure is indicated, but not as specified, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS  . If fuel pressure is not present, go to FUEL SYSTEM.
  9. Check for fuel contamination. If fuel is contaminated, clean fuel system. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If fuel is not contaminated, go to next step.
  10. Install Spark Tester (J-26792) to cylinder No. 1, 2 and 3 (one at a time). Connect the spark plug wire of companion cylinder to ground (i.e., 1/4, 2/5, 3/6). Crank engine and observe spark tester. If spark is present, go to next step. If spark is not present, go to step 12).
  11. Remove and inspect spark plugs from all cylinders. If spark plugs are okay, go to step 37). If spark plugs shows excessive fouling, check engine for mechanical problems.
  12. If spark is present at any ignition wire, go to next step. If spark is not present at any ignition wire, go to step 40).
  13. Remove and inspect ignition coil to affected cylinder for cracks or carbon tracking. Replace faulty ignition coil(s) as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If coil(s) are okay, go to next step.
  14. Check secondary ignition resistance. Resistance should be 5000-8000 ohms. Replace faulty ignition coil(s) as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If resistance is as specified, go to next step.
  15. Remove and inspect ignition wire to affected cylinder for cracks or carbon tracking. Replace faulty ignition wire(s) as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If wire(s) are okay, go to next step.
  16. Check ignition wire resistance. Resistance should be about 30,000 ohms. Replace faulty ignition wire(s) as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If resistance is not as specified, go to next step.
  17. Connect test light across Ignition Control Module (ICM) primary circuit (between ICM control terminals) for coils associated with cylinder that did not have a spark. Crank engine. If test light flashes, go to step 39). If test light does not flash, go to step 40).
  18. Turn ignition off. Disconnect PCM connector. Turn ignition on. Observe injector test lights. If injector test lights illuminate, go to step 34). If injector test lights does not illuminate, go to step 38).
  19. If any injector test light flashes, go to next step. If no injector test light flashes, go to step 22).
  20. Disconnect injector test light that did not flash when engine was being cranked. Turn ignition on. Using a test light connected to ground, probe ignition feed circuit at each injector connector. See the WIRING DIAGRAMS article. If test light illuminates on all injector connectors, go to next step. If test light does not illuminate on all injector connectors, go to step 35).
  21. Turn ignition off. Disconnect PCM connector. Check affected injector circuit driver for an open. See the WIRING DIAGRAMS article. Repair open circuit as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit is okay, go to step 38).
  22. Turn ignition off. Disconnect Ignition Control Module (ICM) connector. Turn ignition on. Using a test light connected to ground, probe ignition control module ignition feed circuit at connector. See the WIRING DIAGRAMS article. If test light illuminates, go to step 24). If test light does not illuminate, go to next step.
  23. Check fuse to ignition control module feed circuit. See the WIRING DIAGRAMS article. If fuse is faulty, locate and repair short to ground in ignition feed circuit. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If fuse is okay, go to step 36).
  24. Install an injector test light to any injector connector. Turn ignition on. Using a test light connected to battery voltage, repeatedly touch test light to 3X reference circuit at ICM connector. See the WIRING DIAGRAMS article. If injector test light flashes, go to next step. If injector test light does not flash, go to step 33).
  25. Turn ignition off. Using a fused jumper wire, jumper Crankshaft Position (CKP) sensor ignition feed circuit at ICM connector to battery voltage. Connect a second jumper between ground and CKP sensor ground circuit at ICM connector. Connect DVOM between battery voltage and CKP sensor signal circuit at ICM connector. Crank engine and observe DVOM voltage reading. Voltage should be 1-3 volts. If voltage reading is as specified, go to step 29). If voltage reading is not as specified, go to next step.
  26. If voltage reading is greater than 3 volts, go to next step. If voltage reading is less than 3 volts, go to step 28).
  27. Disconnect CKP sensor connector. Using a test light connected to battery voltage, probe CKP sync signal circuit. See the WIRING DIAGRAMS article. If test light illuminates, locate and repair short to ground in CKP sync signal circuit. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If test light does not illuminate, go to step 41).
  28. Check open or short to voltage in CKP sensor sync signal circuit, open in CKP sensor ground circuit, or open or short to ground in CKP sensor feed circuit. See the WIRING DIAGRAMS article. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If no circuit problems are found, go to step 41).
  29. Connect DVOM between battery voltage and 18X reference circuit at ICM connector. Crank engine and observe DVOM voltage reading. Voltage should be 5-7 volts. If voltage reading is as specified, go to step 40). If voltage reading is not as specified, go to next step.
  30. If voltage reading is greater than 7 volts, go to next step. If voltage reading is less than 7 volts, go to step 32).
  31. Disconnect CKP sensor connector. Using a test light connected to battery positive, probe 18X reference circuit terminal. See the WIRING DIAGRAMS article. If test light illuminates, locate and repair short to ground in 18X reference circuit. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit is okay, go to step 41).
  32. Check for open or short to voltage in 18X reference circuit. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit is okay, go to step 41).
  33. Turn ignition off. Disconnect PCM connector. Check for open or short in 3X reference circuit. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit is okay, go to step 38).
  34. Locate and repair short to ground in injector driver circuit(s) to affected injector (test light stayed on). See the WIRING DIAGRAMS article. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  35. Locate and repair open in fuel injector ignition feed circuit. See the WIRING DIAGRAMS article. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  36. Locate and repair open in ICM ignition feed circuit. See the WIRING DIAGRAMS article. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  37. Repair engine mechanical problem. Check for bent push rods, faulty or incorrect camshaft, leaking or sticky valves or rings, excessive valve deposits, loose or worn rocker arms, weak valve springs, incorrect valve timing or a leaking head gasket. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  38. Replace PCM. Perform PCM relearn procedures. After replacing PCM, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  39. Replace affected ignition coil(s) that did not produce a spark. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  40. Replace ICM. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  41. Replace CKP sensor. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
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