MIL Circuit Troubleshooting
MIL Circuit Troubleshooting1. Turn the ignition switch ON (II).
2. Do the gauge self-diagnostic procedure.
Does the MIL indicator flash?
YES - Go to step 3.
NO - Substitute a known-good gauge control module, and recheck. If the MIL circuit is OK, replace the original gauge control module.
3. Turn the ignition switch OFF.
4. Turn the ignition switch ON (II), and watch the MIL.
Does the MIL stay off?
YES - Go to step 17.
NO - Go to step 5.
5. Turn the ignition switch OFF.
6. Turn the ignition switch ON (II), wait 20 seconds, and watch the MIL.
Does the MIL stay on more than 20 seconds or flash more than 5 times?
YES - Go to step 7.
NO - The MIL circuit is OK.
7. Turn the ignition switch OFF.
8. Connect the HDS.
9. Turn the ignition switch ON (II), and read the HDS.
Does the HDS communicate with the PCM?
YES - Go to step 10.
NO - Go to "DLC Circuit Troubleshooting".
10. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - Go to the indicated DTC's troubleshooting.
NO - Go to step 11.
11. Check the MIL in the DATA LIST with the HDS.
Does it indicate ON?
YES - Go to step 12.
NO - Substitute a known-good gauge control module, and recheck. If the MIL circuit is OK, replace the original gauge control module.
12. Check the SCS in the DATA LIST with the HDS.
Is a short indicated?
YES - Go to step 13.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
13. Turn the ignition switch OFF.
14. Jump the SCS line with the HDS.
15. Disconnect ECM connector E (31P).
16. Check for continuity between PCM connector terminal E16 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (E16) and the DLC.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
17. Try to start the engine.
Does the engine start and idle smoothly?
YES - Go to step 18.
NO - Go to step 22.
18. Turn the ignition switch OFF.
19. Connect the HDS.
20. Turn the ignition switch ON (II), and read the HDS.
Does the HDS communicate with the PCM?
YES - Go to step 21.
NO - Go to "DLC Circuit Troubleshooting".
21. Check for Temporary DTCs or DTCs with the HDS.
Is DTC U0073 and/or U0155 indicated?
YES - Go to the indicated DTC's troubleshooting.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
22. Turn the ignition switch OFF.
23. Inspect the No. 23 +B IG MAIN (50 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES - Repair open in the wire between the No. 23 +B IG MAIN (50 A) fuse and the ignition switch. If the wire is OK, go to step 24.
NO - Repair short in the wire between the No. 23 +B IG MAIN (50 A) fuse and the under-dash fuse/relay box. Also replace the No. 23 +B IG MAIN (50 A)fuse.
24. Inspect the No. 8 FI ECU (PCM) (15 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES - Go to step 31.
NO - Go to step 25.
25. Remove the blown No. 8 FI ECU (PCM) (15 A) fuse from the under-dash fuse/relay box.
26. Remove the left kick panel, then remove PGM-FI main relay 1 (FI MAIN) (A) from the under-dash fuse/relay box.
27. Check for continuity between body ground and PGM-FI main relay 1 (FI MAIN) 4P connector terminals No. 1 and No. 3 individually.
Is there continuity?
YES - Repair short in the wire between the No. 8 FI ECU (PCM) (15 A) and PGM-FI main relay 1 (FI MAIN). Also replace the No. 8 FI ECU (PCM) (15 A)fuse.
NO - Go to step 28.
28. Disconnect each of the components or connectors below, one at a time, and check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No. 2 and body ground.
- PGM-FI main relay 2 (FUEL PUMP)
- PCM connector A (31P)
- Each injector 2P connector
- Camshaft position (CMP) sensor 3P connector
- Crankshaft position (CKP) sensor A/B 6P connector
- A/F sensor relay
- Throttle actuator control module relay
Does continuity go away when one of the above components is disconnected?
YES - Replace the component that made the short to body ground go away when disconnected. If the item is the PCM, update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM. Also replace the No. 8 FI ECU (PCM) (15 A) fuse.
NO - Go to step 29.
29. Disconnect the connectors of these components:
- PGM-FI main relay 2 (FUEL PUMP)
- PCM connector A (31P)
- Injectors
- Camshaft position (CMP) sensor
- Crankshaft position (CKP) sensor A/B
- A/F sensor relay
- Throttle actuator control module relay
30. Check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No. 2 and body ground.
Is there continuity?
YES - Repair short in the wire between PGM-FI main relay 1 (FI MAIN) and each item. Also replace the No. 8 FI ECU (PCM)(15 A) fuse.
NO - Replace PGM-FI main relay 1 (FI MAIN). Also replace the No. 8 FI ECU (PCM) (15 A) fuse.
31. Turn the ignition switch ON (II).
32. Measure voltage between PCM connector terminal D6 and body ground.
Is there battery voltage?
YES - Go to step 33.
NO - Repair open in the wire between the No, 19 FUEL PUMP (15 A) fuse and the PCM (D6).
33. Measure voltage between PCM connector terminal E5 and body ground.
Is there battery voltage?
YES - Go to step 40.
NO - Go to step 34.
34. Turn the ignition switch OFF.
35. Remove the left kick panel. Then remove PGM-FI main relay 1 (PI MAIN) (A) from the under-dash fuse/relay box.
36. Measure voltage between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No. 3 and body ground.
Is there battery voltage?
YES - Go to step 37.
NO - Repair open in the wire between the No. 8 FI ECU (PCM) (15 A) fuse and PGM-PI main relay (FI MAIN).
37. Jump the SCS line with the HDS.
38. Disconnect PCM connector E (31P).
39. Check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No. 4 and PCM connector terminal E5.
Is there continuity?
YES - Test PGM-FI main relay 1 (FI MAIN) . If the relay is OK, update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
NO - Repair open in the wire between PGM-FI main relay 1 (FI MAIN) and the PCM (E5).
40. Turn the ignition switch ON (II).
41. Measure voltage between body ground and PCM connector terminal A4.
Is there battery voltage?
YES - Go to step 50.
NO - Go to step 42.
42. Turn the ignition switch OFF.
43. Remove the left kick panel. Then remove PGM-FI main relay 1 (FI MAIN) (A) from the under-dash fuse/relay box.
44. Turn the ignition switch ON (II).
45. Measure voltage between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 46.
NO - Repair open in the wire between the No. 8 FI ECU (PCM) (15 A) fuse and PGM-FI main relay 1 (FIMAIN).
46. Turn the ignition switch OFF.
47. Jump the SCS line with the HDS.
48. Disconnect PCM connector A (31P).
49. Check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No. 2 and PCM connector terminal A4.
Is there continuity?
YES - Replace PGM-FI main relay 1 (PI MAIN).M
NO - Repair open in the wire between PGM-FI main relay 1 (FI MAIN) and the PCM (A4).
50. Measure voltage between body ground and PCM connector terminals A1, A2,A3, and D16 individually.
Is there more than 0.2 V?
YES - Repair open in the wire(s) that had more than 0.2V between G101 and the PCM (A1, A2, A3, and D161.
NO - Go to step 51.
51. Measure voltage between body ground and PCM connector terminal A12.
Is there about 5 V?
YES - Go to step 59.
NO - Go to step 52.
52. Turn the ignition switch OFF.
53. Disconnect the connector from each of the following sensors, one at a time, and measure voltage between body ground and PCM connector terminal A12 with the ignition switch ON (II).
- Manifold absolute pressure (MAP) sensor
- Output shaft (countershaft) speed sensor
Is there about 5 V?
YES - Replace the sensor that restored 5V when disconnected.
NO - Go to step 54.
54. Turn the ignition switch OFF.
55. Jump the SCS line with the HDS.
56. Disconnect the connectors from these sensors:
- Manifold absolute pressure (MAP) sensor
- Output shaft (countershaft) speed sensor
57. Disconnect PCM connector A (31P).
58. Check for continuity between PCM connector terminal A12 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (A12) and the MAP sensor or the output shaft (countershaft) speed sensor.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
59. Measure voltage between body ground and PCM connector terminal C13.
Is there about 5V?
YES - Go to step 67.
NO - Go to step 60.
60. Turn the ignition switch OFF.
61. Disconnect the connector from each of the following sensors, one at a time, and measure voltage between body ground and PCM connector terminal C13 with the ignition switch ON (II).
- Accelerator pedal position (APP) sensor
- Intake manifold tuning (IMT) actuator
- Exhaust gas recirculation (EGR) valve
- Engine oil pressure (EOP) sensor
- Fuel tank pressure (FTP) sensor
- Input shaft (mainshaft) speed sensor
Is there about 5 V?
YES - Replace the part that restored 5V when disconnected.
NO - Go to step 62.
62. Turn the ignition switch OFF.
63. Jump the SCS line with the HDS.
64. Disconnect the connectors from these sensors:
- Accelerator pedal position (APP) sensor
- Intake manifold tuning (IMT) actuator
- Exhaust gas recirculation (EGR) valve
- Engine oil pressure (EOP) sensor
- Fuel tank pressure (FTP) sensor
- Input shaft (mainshaft) speed sensor
65. Disconnect PCM connector C (22P).
66. Check for continuity between PCM connector terminal C13 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (C13) and the APP sensor, the EOP sensor, the IMT actuator, the EGR valve, the FTP sensor, or the input shaft (mainshaft) speed sensor.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
67. Measure voltage between body ground and PCM connector terminal C6.
Is there about 5 V?
YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
NO - Go to step 68.
68. Turn the ignition switch OFF.
69. Disconnect the APP sensor 6P connector, and measure voltage between body ground and PCM connector terminal C6 with the ignition switch ON (II).
Is there about 5V?
YES - Replace the APP sensor.
NO - Go to step 70.
70. Turn the ignition switch OFF.
71. Jump the SCS line with the HDS.
72. Disconnect the APP sensor 6P connector.
73. Disconnect PCM connector C (22P).
74. Check for continuity between PCM connector terminal C6 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (C6)and the APP sensor.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.