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 assembly, and recheck. If the MIL circuit is OK, replace the original gauge assembly.
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 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 ECM/PCM?
YES - Go to step 10.
NO - Go to "DLC Circuit Troubleshooting". If no problem is found in the DLC troubleshooting, go to step 21.
10. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - Go to the DTC Troubleshooting Index. Diagnostic Trouble Code Descriptions
NO - Go to step 11.
11. Check the MIL in the DATA LIST with the HDS.
Is ON indicated?
YES - Go to step 12.
NO - Substitute a known-good gauge assembly, and recheck. If the MIL circuit is OK, replace the original gauge assembly.
12. Check the SCS in the DATA LIST with the HDS.
Is a short indicated?
YES - Go to step 13.
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
13. Turn the ignition switch OFF.
14. Jump the SCS line with the HDS.
15. Disconnect ECM/PCM connector E (31P).
16. Check for continuity between ECM/PCM connector terminal E29 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (E29) and the DLC.
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
17. Try to start the engine.
Did the engine not start, or does it idle rough?
YES - Go to step 22.
NO - Go to step 18.
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 ECM/PCM?
YES - Go to step 21.
NO - Go to "DLC Circuit Troubleshooting". If no problem is found in the DLC troubleshooting, go to step 21.
21. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.
Is DTC U0073 and/or U0155 indicated?
YES - Go to the indicated DTC troubleshooting.
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/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. 20 IG (50 A) fuse and the ignition switch. If the wire is OK, go to step 24.
NO - Repair short in the wire between 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 (ECM/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 (ECM/PCM) (15 A) fuse from the under-dash fuse/relay box.
26. Remove the kick panel , then remove PGM-FI main relay 1 (FI MAIN) (A) from the under-hood fuse/relay box.
27. Check for continuity between body ground and PGM-FI main relay 1 (FI MAIN) 4P connector terminals No.2 and No.3 individually.
Is there continuity?
YES - Repair short in the wire between the No.8 FI ECU (ECM/PCM) (15 A) fuse and PGM-FI main relay 1. Also replace the No.8 FI ECU (ECM/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.1 and body ground.
- PGM-FI main relay 2 (FUEL PUMP)
- ECM/PCM connector A (31P)
- Each injector 2P connector
- Camshaft position (CMP) sensor B 3P connector
- Crankshaft position (CKP) sensor 3P connector
Is there continuity?
YES - Go to step 29.
NO - Replace the component that made the short to body ground go away when disconnected. If the item is the ECM/PCM, update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
Also replace the No.8 FI ECU (ECM/PCM) (15 A) fuse.
29. Disconnect the connectors from these components
- PGM-FI main relay 2 (FUEL PUMP)
- ECM/PCM connector A (31P)
- Injectors
- Camshaft position (CMP) sensor B
- Crankshaft position (CKP) sensor
30. Check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No.1 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 (ECM/PCM) (15 A) fuse.
NO - Replace PGM-FI main relay 1 (FI MAIN). Also replace the No.8 FI ECU (ECM/PCM) (15 A) fuse.
31. Inspect the No.19 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES - Go to step 44.
NO - Go to step 32.
32. Remove the blown No.19 FUEL PUMP (15 A) fuse from the under-dash fuse/relay box.
33. Jump the SCS line with the HDS.
34. Disconnect ECM/PCM connector E (31P).
35. Check for continuity between ECM/PCM connector terminal E9 and body ground.
Is there continuity?
YES - Go to step 36.
NO - Replace the No.19 FUEL PUMP (15 A) fuse, and update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
36. Remove the left kick panel , then remove PGM-FI main relay 2 (FUEL PUMP) (A) from the under-hood fuse/relay box.
37. Check for continuity between ECM/PCM connector terminal E9 and body ground.
Is there continuity?
YES - Repair short in the wire between the No.19 FUEL PUMP (15 A) fuse and the ECM/PCM (E9), or between the No.19 FUEL PUMP (15 A) fuse and PGM-FI main relay 2 (FUEL PUMP). Also replace the No.19 FUEL PUMP (15 A) fuse.
NO - Go to step 38.
38. Remove the trunk floor trim panel.
39. Remove the access panel from the floor.
40. Disconnect the fuel pump 5P connector.
41. Check for continuity between fuel pump 5P connector terminal No.8 and body ground.
Is there continuity?
YES - Repair short in the wire between the fuel pump and PGM-FI main relay 2 (FUEL PUMP). Also replace the No.19 FUEL PUMP (15 A) fuse.
NO - Go to step 42.
42. Reinstall PGM-FI main relay 2 (FUEL PUMP) (A).
43. Check for continuity between fuel pump 5P connector terminal No. 5 and body ground.
Is there continuity?
YES - Replace PGM-FI main relay 2 (FUEL PUMP). Also replace the No.19 FUEL PUMP (15 A) fuse.
NO - Check the fuel pump, and replace it if necessary. Also replace the No.19 FUEL PUMP (15 A) fuse.
44. Jump the SCS line with the HDS.
45. Disconnect ECM/PCM connector E (31P).
46. Turn the ignition switch ON (II).
47. Measure voltage between ECM/PCM connector terminal E9 and body ground.
Is there battery voltage?
YES - Go to step 48.
NO - Repair open in the wire between the No.19 FUEL PUMP (15 A) fuse and the ECM/PCM (E9).
48. Measure voltage between ECM/PCM connector terminal E7 and body ground.
Is there battery voltage?
YES - Go to step 53.
NO - Go to step 49.
49. Turn the ignition switch OFF.
50. Remove left the kick panel , then remove PGM-FI main relay 1 (FI MAIN) (A) from the under-hood fuse/relay box.
51. 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 52.
NO - Repair open in the wire between the No.8 FI ECU (ECM/PCM) (15 A) fuse and PGM - FI main relay 1.
52. Check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No.4 and ECM/PCM connector terminal E7.
Is there continuity?
YES - Test PGM-FI main relay 1 (FI MAIN). If the relay is OK, update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
NO - Repair open in the wire between PGM-FI main relay 1 (FI MAIN) and the ECM/PCM (E7).
53. Reconnect ECM/PCM connector E (31P).
54. Turn the ignition switch ON (II).
55. Measure voltage between body ground and ECM/PCM connector terminals A2 and A3 individually.
Is there battery voltage?
YES - Go to step 62.
NO - Go to step 56.
56. Turn the ignition switch OFF.
57. Remove PGM-FI main relay 1 (FI MAIN) (A).
58. Turn the ignition switch ON (II).
59. Measure voltage between PGM-FI main relay 1 4P connector terminal No.2 and body ground.
Is there battery voltage?
YES - Go to step 60.
NO - Repair open in the wire between the No.8 FI ECU (ECM/PCM) (15 A) fuse and PGM-FI main relay 1 (FI MAIN).
60. Turn the ignition switch OFF.
61. Check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No.1 and ECM/PCM connector terminals A2 and A3 individually.
Is there continuity?
YES - Replace PGM-FI main relay 1 (FI MAIN).
NO - Repair open in the wire between PGM-FI main relay 1 (FI MAIN) and the ECM/PCM (A2, A3).
62. Measure voltage between body ground and ECM/PCM connector terminals A4, A5, A8, and A9 individually.
Is there more than 0.2 V?
YES - Repair open in the wire(s) that had more than 0.2 V between G101 and the ECM/PCM (A4, A5, A8, A9).
NO - Go to step 63.
63. Measure voltage between body ground and ECM/PCM connector terminal A21.
Is there more than 5 V?
YES - Go to step 71.
NO - Go to step 64.
64. Turn the ignition switch OFF.
65. Disconnect the connector from each of these sensors, one at a time, and measure voltage between body ground and ECM/PCM connector terminal A21 with the ignition switch ON (II).
- Manifold absolute pressure (MAP) sensor
- Accelerator pedal position (APP) sensor
- Mainshaft speed sensor (A/T)
Is there about 5 V?
YES - Replace the sensor that restored 5 V when disconnected.
NO - Go to step 66.
66. Turn the ignition switch OFF.
67. Jump the SCS line with the HDS.
68. Disconnect the connectors from the following sensors.
- Manifold absolute pressure (MAP) sensor
- Accelerator pedal position (APP) sensor
- Mainshaft speed sensor (A/T)
69. Disconnect ECM/PCM connector A (31P).
70. Check for continuity between ECM/PCM connector terminal A21 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (A21) and the MAP sensor, APP sensor or mainshaft speed sensor (A/T).
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good, ECM/PCM, then recheck. If the symptom/indication does away with a known-good ECM/PCM, replace the original ECM/PCM.
71. Measure voltage between body ground and ECM/PCM connector terminal A20.
Is there about 5 V?
YES - Go to step 79.
NO - Go to step 72.
72. Turn the ignition switch OFF.
73. Disconnect the connector from each of these sensors, one at a time, and measure voltage between body ground and ECM/PCM connector terminal A20 with the ignition switch ON (II).
- Throttle position (TP) sensor
- Accelerator pedal position (APP) sensor
- Countershaft speed sensor
Is there about 5 V?
YES - Replace the sensor that restored 5 V when disconnected.
NO - Go to step 74.
74. Turn the ignition switch OFF.
75. Jump the SCS line with the HDS.
76. Disconnect the connector from the following sensors.
- Throttle position (TP) sensor
- Accelerator pedal position (APP) sensor
- Countershaft speed sensor
77. Disconnect ECM/PCM connector A (31P).
78. Check for continuity between ECM/PCM connector terminal A20 and body ground
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (A20) and the TP sensor, APP sensor, EGR valve or countershaft speed sensor.
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known good, ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM
79. Measure voltage between body ground and ECM/PCM connector terminal E5.
Is there about 5 V?
YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good, ECM/PCM, then recheck. If the symptom/indication goes away with a known good ECM/PCM, replace the original ECM/PCM.
NO - Go to step 80.
80. Turn the ignition switch OFF.
81. Disconnect the FTP sensor 3P connector, and measure voltage between body ground and ECM/PCM connector terminal E5 with the ignition switch ON (II).
Is there about 5 V?
YES - Replace the FTP sensor.
NO - Go to step 82.
82. Turn the ignition switch OFF.
83. Jump the SCS line with the HDS.
84. Disconnect the FTP sensor 3P connector.
85. Disconnect ECM/PCM connector E (31P).
86. Check for continuity between ECM/PCM connector terminal E5 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (E5) and FTP sensor.
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good, ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.