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Ignition System

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
  2. Using scan tool, check for Diagnostic Trouble Codes (DTCs). If DTC P0601, P0602, P1621 or P1629 is present, diagnose DTCs first. See appropriate SELF-DIAGNOSTICS article. If DTCs are not present, go to next step.
  3. Check PCM ground connection at engine block. If ground connection is okay, go to next step. If ground connection is faulty, go to step  5 .
  4. Check F/P-INJ and IGN fuses (20-amp), located in instrument panel fuse block. If fuses are okay, go to step  6 . If fuses are faulty, go to step  7 .
  5. Repair PCM ground connection. After repairs, go to step  43 .
  6. Check fuel level and add fuel if necessary. If fuel level is okay, go to step  8 . If fuel level was low and needed to be added, go to step  43 .
  7. Check for short to ground in appropriate circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. Replace faulty fuse. After repairs, go to step  43 .
  8. Install scan tool. Turn ignition on, leaving engine off. Ensure throttle is closed. Monitor Throttle Position (TP) sensor voltage. If TP sensor voltage is less than one volt, go to next step. If TP sensor voltage is not less than one volt, go to DTC P0123. See appropriate SELF-DIAGNOSTICS article.
  9. Using scan tool, monitor Engine Coolant Temperature (ECT) sensor and Intake Air Temperature (IAT) sensor values. If sensor values are about the same, go to next step. If sensor values are not about the same, go to DTC P0118. See appropriate SELF-DIAGNOSTICS article.
  10. Using scan tool, ensure MAP sensor voltage is greater than 4 volts with ignition on. Crank engine. If serial data is lost while cranking engine, or if MAP sensor voltage is not greater than 4 volts, go to step  13 . If MAP sensor value is greater than 4 volts and serial data was not lost during cranking, go to next step.
  11. Using scan tool, ensure MAP sensor voltage is greater than 4 volts with ignition on. Crank engine. If MAP sensor voltage changes while cranking engine, go to next step. If MAP sensor voltage is not greater than 4 volts, or does not change while cranking engine, diagnose MAP sensor. See appropriate SYSTEM & COMPONENT TESTING article.
  12. Using scan tool, check Crankshaft Position (CKP) sensor activity while cranking engine. If CKP ACTIVITY COUNTER increments while cranking, go to step  14 . If CKP ACTIVITY COUNTER does not increment, go to step  24 .
  13. Repair voltage loss to PCM from ignition switch. After repairs, go to step  43 .
  14. Turn ignition off. Disconnect 2-pin Ignition Control Module (ICM) harness connector. Check ICM ground circuit for an open or short to power. See appropriate wiring diagram in WIRING DIAGRAMS article. If ground circuit is okay, go to next step. If ground circuit is not okay, repair as necessary and go to step  43 .
  15. Reconnect ICM harness connector. Install Spark Tester (J-26792) to cylinder No. 1, leaving other spark plug wires connected to spark plugs. Crank engine and check for spark. Repeat procedure for remaining cylinders. If spark is present at all wires, go to step  39 . If spark is not present at all wires, go to step  27 .
  16. Turn ignition off. Disconnect 6-pin Ignition Control Module (ICM) harness connector. Connect DVOM between ICM harness connector CKP sensor ground terminal and CKP sensor signal terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. Check combined CKP sensor and harness resistance. Resistance should be 700-1300 ohms. If resistance is as specified, go to step  18 . If resistance is not as specified, go to next step.
  17. Remove CKP sensor. Using DVOM, check CKP sensor resistance. Resistance should be 700-1300 ohms. If resistance is as specified, go to step  20 . If resistance is not as specified, go to step  21 .
  18. Set DVOM to AC scale. Connect DVOM between ICM connector CKP sensor ground terminal and CKP sensor signal terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. Crank engine. Voltage reading should be greater than 200 millivolts. If voltage reading is as specified, go to next step. If voltage reading is not as specified, go to step  23 .
  19. Check CKP sensor signal circuit for a short to power. See appropriate wiring diagram in WIRING DIAGRAMS article. If CKP sensor signal circuit is okay, go to next step. If CKP sensor signal circuit is not okay, repair as necessary and go to step  43 .
  20. Check CKP sensor signal circuit for a short to ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If CKP sensor signal circuit is okay, go to next step. If CKP sensor signal circuit is not okay, repair as necessary and go to step  43 .
  21. Using a test light connected to ICM connector 7X reference signal terminal, touch battery ground terminal, and then battery positive terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. Monitor CKP ACTIVITY COUNTER increment on scan tool. If CKP ACTIVITY COUNTER increments as test light is touched to battery positive, go to step  31 . If CKP ACTIVITY COUNTER does not increment, go to step  25 .
  22. Repair open or short in CKP sensor wiring harness. After repairs, go to step  43 .
  23. Replace CKP sensor. After replacing CKP sensor, go to step  43 .
  24. Turn ignition off. Disconnect 2-pin Ignition Control Module (ICM) harness connector. Turn ignition on. Using a test light connected to ground, probe ICM harness connector ignition positive voltage terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step  16 . If test light does not illuminate, go to step  26 .
  25. Check CKP sensor 7X reference signal circuit for an open or short. See appropriate wiring diagram in WIRING DIAGRAMS article. If CKP sensor 7X reference signal circuit is okay, go to step  33 . If CKP sensor 7X reference signal circuit is not okay, repair as necessary and go to step  43 .
  26. Repair faulty ICM ignition positive voltage circuit. After repairs, go to step  43 .
    27. CAUTION: DO NOT leave test light connected to PCM harness connector ignition control circuit for more than 5 seconds at a time as ignition coil and/or Ignition Control Module (ICM) may be damaged.
  27. Turn ignition off. Disconnect Powertrain Control Module (PCM) harness connectors. Connect spark tester to spark plug wire that did not show spark. Turn ignition on. Using a test light connected to battery positive, momentarily touch affected ignition control circuit with test light. A spark should jump across spark tester. If a spark jumps across tester, go to step  33 . If a spark does not jump across tester, go to step  34 .
  28. Measure resistance of spark plug wire that would not produce spark with spark tester. If resistance is less than 30,000 ohms, go to next step. If resistance is greater than 30,000 ohms, go to step  37 .
  29. Check secondary resistance of ignition coil that did not produce a spark. Resistance should be 5000-8000 ohms. If resistance is not as specified, go to step  38 . If resistance is as specified, go to next step.
  30. Reconnect ICM and PCM harness connectors. Using a test light, backprobe ignition coil terminals at ICM harness connector. Crank engine and observe test light. If test light flashes, go to step  38 . If test light does not flash, go to next step.
  31. Check ICM harness connectors for poor connections. If connections are okay, go to next step. If connections are not okay, repair as necessary and go to step  43 .
  32. Replace ICM. After replacing ICM, go to step  43 .
  33. Check for faulty PCM harness connectors or connections. If connectors and connections are okay, go to step  36 . If connectors and connections are faulty, go to step  35 .
  34. Check ignition control circuit of faulty cylinder for an open or short. If ignition control circuit is okay, go to step  28 . If ignition control circuit is not okay, repair as necessary and go to step  43 .
  35. Repair harness connectors or connections. After repairs, go to step  43 .
  36. Replace PCM. Perform PCM relearn procedures. After replacing PCM, go to step  43 .
  37. Replace faulty spark plug wires. After repairs, go to step  43 .
  38. Replace faulty ignition coils. After repairs, go to step  43 .
  39. Disconnect all fuel injector harness connectors. Connect injector test light to injectors No. 1, 2, 3 and 4 (one at a time). Crank engine and observe injector test light. If test light flashed on all tests, go to next step. If test light did not flash on all tests, go to step  42 .
  40. Install fuel pressure gauge. Turn ignition on and note fuel pressure after 2 seconds. Fuel pressure should be 41-47 psi (2.9-3.3 kg/cm2 ). If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to FUEL SYSTEM ELECTRICAL CIRCUIT  .
  41. Check for fouled spark plugs. If spark plugs are okay, check for water in fuel system. Check for basic engine problem (low compression, etc.). Ensure spark plugs are of resistor type. Check fuel pump operation with scan tool. If spark plugs are fouled, replace as necessary and go to step  43 .
  42. Repair open in fuel pump and injector ignition feed circuit. After repairs, go to next step.
  43. Using scan tool, clear DTC(s). Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls, go to step  2 .
  44. Allow engine to reach normal operating temperature. Check for DTCs. If DTCs are present, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If DTCs are not present, system is okay.
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