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 more than 20 seconds or flash more than five times?
YES - Go to step 7.
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) and the HDS.
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), the ABS control unit, the SRS unit, and the service check connector.
NO - Go to step 14.
14. Disconnect the gauge assembly 22P connector.
15. Check for continuity between ECM/PCM connector terminal E31 and body ground.
Is there continuity?
YES - Repair shorten 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 17.
NO - Go to step 25.
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 to "DLC Circuit Troubleshooting".
25. Inspect the No.20 IG (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 26.
NO - Repair short in the wire between No.20 IG (50 A) fuse and the under-hood fuse/relay box. Also replace the No.20 IG (50 A) fuse.
26. Turn the ignition switch OFF.
27. Inspect the IGP (15 A) fuse in under-hood subfuse/relay box A.
Is the fuse OK?
YES - Go to step 34.
NO - Go to step 28.
28. Remove the blown IGP (15 A) fuse in underhood subfuse/relay box A.
29. Remove the glove box. Remove PGM-FI main relay 1(A).
30. Check for continuity between body ground and PGM-FI main relay 1 4P connector terminals No.2 and No.4 individually.
Is there continuity?
YES -
- Repair short in the wire between the IGP (15 A) fuse and PGM-FI main relay 1. Also replace the IGP (15 A) fuse.
- Repair short in the wire between the IGP (15 A) fuse and the No.2 ENG (30 A) fuse. Also replace the No.2 ENG (30 A) fuse.
NO - Go to step 31.
31. Disconnect each of the components or the connectors below, one at a time, and check for continuity between PGM-FI main relay 1 4P connector terminal No.1 and body ground.
- PGM-FI main relay 2
- ECM/PCM connector A (31 P)
- Each injector 2P connector
- Throttle actuator control module relay
- Camshaft position (CMP) sensor B 3P connector
- Crankshaft position (CKP) sensor 3P connector
Is there continuity?
YES - Go to step 32.
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 IGP (15 A) fuse.
32. Disconnect the connectors of all these components:
- PGM-FI main relay 2
- ECM/PCM connector A (31 P)
- Injectors
- Throttle actuator control module relay
- CMP sensor B
- CKP sensor
33. Check for continuity between PGM-FI main relay 1 4P connector terminal No.1 and body ground.
Is there continuity?
YES - Repair short in the wire between PGM-FI main relay 1 and each item. Also replace the IGP (15 A) fuse or the No.2 ENG (30 A) fuse.
NO - Replace PGM-FI main relay 1. Also replace the IGP (15 A) fuse or the No.2 ENG (30 A) fuse.
34. Inspect the No.17 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES - Go to step 47.
NO - Go to step 35.
35. Remove the blown No.17 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.
36. Jump the SCS line with the HDS.
37. Disconnect ECM/PCM connector E (31 P).
38. Check for continuity between ECM/PCM connector terminal E9 and body ground.
Is there continuity?
YES - Go to step 39.
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.
39. Remove the glove box, then remove PGM-FI main relay 2 (A).
40. 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, ECM/PCM (E9), and the PGM-FI main relay 2. Also replace the No.17 FUEL PUMP (15 A) fuse.
NO - Go to step 41.
41. Fold the rear seats forward, and pull back the carpet to expose the access panel.
42. Remove the access panel from the floor.
43. Disconnect the fuel pump 5P connector.
44. 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. Also replace the No.17 FUEL PUMP (15A) fuse.
NO - Go to step 45.
45. Reinstall PGM-FI main relay 2 (A).
46. Check for continuity between fuel pump 5P connector terminal No.5 and body ground.
Is there continuity?
YES - Replace PGM-FI main relay 2. Also replace the No.17 FUEL PUMP (15A) fuse.
NO - Check the fuel pump, and replace it if necessary. Also replace the No.17 FUEL PUMP (15A) fuse.
47. Jump the SCS line with the HDS.
48. Disconnect ECM/PCM connector E (31 P).
49. Turn the ignition switch ON (II).
50. Measure voltage between ECM/PCM connector terminal E9 and body ground.
Is there battery voltage?
YES - Go to step 51.
NO - Repair open in the wire between the No.17 FUEL PUMP (15 A) fuse and the ECM/PCM (E9).
51. Turn the ignition switch OFF.
52. Measure voltage between ECM/PCM connector terminal E7 and body ground.
Is there battery voltage?
YES - Go to step 56.
NO - Go to step 53.
53. Remove the glove box, then remove PGM-FI main relay 1(A).
54. Measure voltage between PGM-FI main relay 1 4P connector terminal No.4 and body ground.
Is there battery voltage?
YES - Go to step 55.
NO -
- Repair open in the wire between the IGP (15 A) fuse and PGM-FI main relay 1.
- Repair open in the wire between the IGP (15 A) fuse and the No.2 ENG (30 A) fuse.
55. Check for continuity between PGM-FI main relay 1 4P connector terminal No.3 and ECM/PCM connector terminal E7.
Is there continuity?
YES - Test PGM-FI main relay 1. 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 PGM-FI main relay 1 and the ECM/PCM (E7).
56. Reconnect ECM/PCM connector E (31 P).
57. Turn the ignition switch ON (II).
58. Measure voltage between body ground and ECM/PCM connector terminals A2 and A3 individually.
Is there battery voltage?
YES - Go to step 65.
NO - Go to step 59.
59. Turn the ignition switch OFF.
60. Remove the glove box, then remove PGM-FI main relay 1(A).
61. Turn the ignition switch ON (II).
62. Measure voltage between PGM-FI main relay 1 4P connector terminal No.2 and body ground.
Is there battery voltage?
YES - Go to step 63.
NO -
- Repair open in the wire between the IGP (15 A) fuse and PGM-FI main relay 1.
- Repair open in the wire between the IGP (15 A) fuse and the No.2 ENG (30 A) fuse.
63. Turn the ignition switch OFF.
64. Check for continuity between PGM-FI main relay 1 4P connector terminal No.1 and ECM/PCM connector terminals A2 and A3 individually.
Is there continuity?
YES - Replace PGM-FI main relay 1.
NO - Repair open in the wire between PGM-FI main relay 1 and the ECM/PCM (A2, A3).
65. 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) that had more than 1.0 V between G101 and the ECM/PCM (A4, A5, A8, A9).
NO - Go to step 66.
66. Turn the ignition switch ON (II).
67. Measure voltage between body ground and ECM/PCM connector terminal A21.
Is there about 5 V?
YES - Go to step 74.
NO - Go to step 68.
68. 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
- Output shaft speed sensor (A/T)
Is there about 5 V?
YES - Replace the sensor that restored 5 V when disconnected.
NO - Go to step 69.
69. Turn the ignition switch OFF.
70. Jump the SCS line with the HDS.
71. Disconnect the connectors from these sensors:
- Manifold absolute pressure (MAP) sensor
- Accelerator pedal position (APP) sensor
- Output shaft speed sensor (A/T)
72. Disconnect ECM/PCM connector A (31 P).
73. 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, the APP sensor or the output shaft 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 goes away with a known-good ECM/PCM, replace the original ECM/PCM.
74. Measure voltage between body ground and ECM/PCM connector terminal A20.
Is there about 5 V?
YES - Go to step 82.
NO - Go to step 75.
75. Turn the ignition switch OFF.
76. 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).
- Accelerator pedal position (APP) sensor
- Input shaft speed sensor (A/T)
Is there about 5 V?
YES - Replace the sensor that restored 5 V when disconnected.
NO - Go to step 77.
77. Turn the ignition switch OFF.
78. Jump the SCS line with the HDS.
79. Disconnect the connector from these sensors:
- Accelerator pedal position (APP) sensor
- Input shaft speed sensor (A/T)
80. Disconnect ECM/PCM connector A (31P).
81. 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 APP sensor or input shaft 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 goes away with a known-good ECM/PCM, replace the original ECM/PCM.
82. 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 83.
83. Turn the ignition switch OFF.
84. 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 85.
85. Turn the ignition switch OFF.
86. Jump the SCS line with the HDS.
87. Disconnect the FTP sensor 3P connector.
88. Disconnect ECM/PCM connector E (31 P).
89. 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.