Malfunction Indicator Lamp: Testing and Inspection
MIL Circuit Troubleshooting1. Turn the ignition switch ON (II), and watch the MIL.
Does the MIL stay off?
YES - Go to step 16.
NO - Go to step 2.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II), and watch the MIL.
Does the MIL stay on for more than 20 seconds?
YES - Go to step 4.
NO - The MIL circuit is OK.
4. Turn the ignition switch OFF.
5. Connect the HDS.
6. Turn the ignition switch ON (II), and read the HDS.
Does the HDS communicate with the ECM/PCM?
YES - Go to step 7.
NO - Go to "DLC Circuit Troubleshooting".
7. 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 8.
8. Check the MIL in the DATA LIST with the HDS.
Is ON indicated?
YES - Go to step 9.
NO - Substitute a known-good gauge assembly, and recheck If the MIL circuit is OK, replace the original gauge assembly.
9. Check the SCS in the DATA LIST with the HDS.
Is a short indicated?
YES - Go to step 10.
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.
10. Turn the ignition switch OFF.
11. Jump the SCS line with the HDS.
12. Disconnect ECM/PCM connector E (31P).
13. 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 DLC.
NO - Go to step 14.
14. Disconnect the gauge assembly B (20P) connector.
15. Check for continuity between ECM/PCM connector terminal E31 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (E31) and the gauge assembly.
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.
16. Try to start the engine.
Does the engine start?
YES - Go to step 25.
NO - Go to step 17.
17. Turn the ignition switch OFF.
18. Connect ECM/PCM connector terminal E31 to body ground with a jumper wire.
19. Turn the ignition switch ON (II).
Is the MIL on?
YES - Go to step 22.
NO - Go to step 20.
20. Turn the ignition switch OFF.
21. Inspect the No.10 METER (7.5 A) fuse in the under dash fuse/relay box.
Is the fuse OK?
YES - Check for an open in the wire between the ECM/PCM (E31) and the gauge assembly Also check for a blown MIL bulb If the wires and the bulb are OK, replace the gauge assembly.
NO - Repair short in the wire between No.10 METER (7.5 A) fuse and the gauge assembly Also replace the No.10 METER (7.5 A) fuse.
22. Turn the ignition switch OFF.
23. Connect the HDS.
24. Turn the ignition switch ON (II), and read the HDS.
Does the HDS communicate with the ECM/PCM?
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 the "DLC Circuit Troubleshooting".
25. Turn the ignition switch OFF.
26. Inspect the No.20 IG (USA: 40 A, Canada: 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 (USA: 40 A, Canada: 50 A) fuse and the ignition switch. If the wires are OK, go to step 27.
NO - Repair short in the wire between No.20 IG (USA: 40 A, Canada: 50 A) fuse and the under-hood fuse/relay box. Also replace the No.20 IG (USA: 40 A, Canada: 50 A) fuse.
27. Turn the ignition switch OFF.
28. Inspect the No.6 ECU (ECM/PCM) (20 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES - Go to step 35.
NO - Go to step 29.
29. Remove the blown No.6 ECU (ECM/PCM) (20 A) fuse in the under-hood fuse/relay box.
30. Remove the glove box. Remove PGM-FI main relay 1 (FI MAIN) (A).
31. Check for continuity between body ground and the PGM-FI main relay 1 (FI MAIN) 4P connector terminals No.2 and No.4 individually.
Is there continuity?
YES - Repair short in the wire between the No.6 ECU (ECM/PCM) (20 A) fuse and the PGM-FI main relay 1 (FI MAIN). Also replace the No.6 ECU (ECM/PCM) (20 A) fuse.
NO - Go to step 32.
32. Disconnect each of the components or the connectors below, one at a time, and check for continuity between the 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
- Idle air control valve 3P connector
- Camshaft position (CMP) sensor B 3P connector
- Crankshaft position (CKP) sensor 3P connector
Is there continuity?
YES - Go to step 33.
NO - Replace the part that made continuity 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.6 ECU (ECM/PCM) (20 A) fuse.
33. Disconnect the connectors of all these components:
- PGM-FI main relay 2 (FUEL PUMP)
- ECM/PCM connector A (31P)
- Injectors
- Idle air control valve
- Camshaft position (CMP) sensor B
- Crankshaft position (CKP) sensor
34. Check for continuity between the 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 the PGM-FI main relay 1 (FI MAIN) and each item. Also replace the No.6 ECU (ECM/PCM) (20 A) fuse.
NO - Replace the PGM-FI main relay 1 (FI MAIN). Also replace the No.6 ECU (ECM/PCM) (20 A) fuse.
35. Inspect the No.17 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES - Go to step 48.
NO - Go to step 36.
36. Remove the blown No.17 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.
37. Jump the SCS line with the HDS.
38. Disconnect ECM/PCM connector E (31P).
39.Check for continuity between ECM connector terminal E9 and body ground.
Is there continuity?
YES - Go to step 40.
NO - Replace the No.17 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 symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
40. Remove the glove box, then remove PGM-FI main relay 2 (FUEL PUMP) (A).
41. Check for continuity between ECM/PCM connector terminal E9 and body ground.
Is there continuity?
YES - Repair short in the wire between the No.17 FUEL PUMP (15 A) fuse and the ECM/PCM (E9), or the PGM-FI main relay 2 (FUEL PUMP). Also replace the No.17 FUEL PUMP (15 A) fuse.
NO - Go to step 42.
42. Remove the rear seat cushion.
43. Remove the access panel from the floor.
44. Disconnect the fuel pump 5P connector.
45. Check for continuity between fuel pump 5P connector terminal No.5 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.17 FUEL PUMP (15 A) fuse.
NO - Go to step 46.
46. Reinstall PGM-FI main relay 2 (FUEL PUMP) (A).
47. 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.17 FUEL PUMP (15 A) fuse.
NO - Check the fuel pump, and replace it if necessary. Also replace the No.17 FUEL PUMP (15 A) fuse.
48. Jump the SCS line with the HDS.
49. Disconnect ECM/PCM connector E (31P).
50. Turn the ignition switch ON (II).
51. Measure voltage between ECM/PCM connector terminals E9 and body ground.
Is there battery voltage?
YES - Go to step 52.
NO - Repair open in the wire between the No.17 FUEL PUMP (15 A) fuse and the ECM/PCM (E9).
52. Turn the ignition switch OFF.
53. Measure voltage between ECM/PCM connector terminal E7 and body ground.
Is there battery voltage?
YES - Go to step 57.
NO - Go to step 54.
54. Remove the glove box, then remove the PGM-FI main relay 1 (FI MAIN) (A).
55. Measure voltage between the PGM-FI main relay 1 (FI MAIN) 4P connector terminal No.4 and body ground.
Is there battery voltage?
YES - Go to step 56.
NO - Repair open in the wire between the No.6 ECU (ECM/PCM) (20 A) fuse and PGM-FI main relay 1 (FI MAIN).
56. Check for continuity between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No.3 and ECM/PCM connector terminal E7.
Is there continuity?
YES - Test the 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 symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
NO - Repair open in the wire between the PGM-FI main relay 1 (FI MAIN) and the ECM/PCM (E7).
57. Reconnect ECM/PCM connector E (31P).
58. Turn the ignition switch ON (II).
59. Measure voltage between body ground and ECM/PCM connector terminals A2 and A3 individually.
Is there battery voltage?
YES - Go to step 66.
NO - Go to step 60.
60. Turn the ignition switch OFF.
61. Remove the glove box, then remove the PGM-FI main relay 1 (FI MAIN) (A).
62. Turn the ignition switch ON (II).
63. Measure voltage between PGM-FI main relay 1 (FI MAIN) 4P connector terminal No.2 and body ground.
Is there battery voltage?
YES - Go to step 64.
NO - Repair open in the wire between the No.6 ECU (ECM/PCM) (20 A) fuse and PGM-FI main relay 1 (FI MAIN)
64. Turn the ignition switch OFF.
65. Check for continuity between the 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).
66. Measure voltage between body ground and ECM/PCM connector terminals A4, A5, A8 and A9 individually.
Is there less than 1.0 V?
YES - Repair open in the wire(s) between that had more than 1.0 V between G101 and the ECM/PCM (A4, A5, A8, A9).
NO - Go to step 67.
67. Turn the ignition switch ON (II).
68. Measure voltage between body ground and ECM/PCM connector terminal A21.
Is there about 5 V?
YES - Go to step 75.
NO - Go to step 69.
69. 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
- Intake manifold tuning (IMT) (intake manifold runner control (IMRC)) valve
- Output shaft (countershaft) speed sensor
Is there about 5 V?
YES - Replace the sensor that restored 5 V when disconnected.
NO - Go to step 70.
70. Turn the ignition switch OFF.
71. Jump the SCS line with the HDS.
72. Disconnect the connectors from the these sensors:
- Manifold absolute pressure (MAP) sensor
- Intake manifold tuning (IMT) (intake manifold runner control (IMRC)) valve
- Output shaft (countershaft) speed sensor
73. Disconnect ECM/PCM connector A (31P).
74. 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, IMT (IMRC) valve or the output shaft (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.
75. Measure voltage between body ground and ECM/PCM connector terminal A20.
Is there about 5 V?
YES - Go to step 83.
NO - Go to step 76.
76. Turn the ignition switch OFF.
77. 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
- Input shaft (mainshaft) speed sensor
Is there about 5 V?
YES - Replace the sensor that restored 5 V when disconnected.
NO - Go to step 78.
78. Turn the ignition switch OFF
79. Jump the SCS line with the HDS
80. Disconnect the connector from these sensors
- Throttle position (TP) sensor
- Input shaft (mainshaft) speed sensor
81. Disconnect ECM/PCM connector A (31P).
82. 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, or input shaft (mainshaft) 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.
83. 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 84.
84. Turn the ignition switch OFF.
85. Disconnect the FTP sensor 3P connector, and measure voltage between body ground and ECM/PCM connector terminal E5with the ignition switch ON (II).
Is there about 5 V?
YES - Replace the FTP sensor.
NO - Go to step 86.
86. Turn the ignition switch OFF.
87. Jump the SCS line with the HDS.
88. Disconnect the FTP sensor 3P connector.
89. Disconnect ECM/PCM connector E (31P).
90. 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.