Part 1 of 2
MIL Circuit Troubleshooting1. Connect an OBD II scan tool/Honda PGM Tester.
2. Turn the ignition switch ON (II), and read the OBD II scan tool/Honda PGM Tester.
Does the OBD II scan tool/Honda PGM Tester communicate with the ECM?
YES - Go to step 3.
NO - Go to "DLC Circuit Troubleshooting".
3. Check the OBD II scan tool/Honda PGM Tester for DTCs.
Are any DTCs indicated?
YES - Go to the DTC Troubleshooting Index. Diagnostic Trouble Code Descriptions
NO - Go to step 4.
4. Turn the ignition switch OFF.
5. Turn the ignition switch ON (II), and watch the malfunction indicator lamp (MIL).
Does the MIL come on and stay on for more than 20 seconds after turning the ignition switch ON (II)?
YES - if the MIL always comes on and stays on, go to step 87. But if the MIL sometimes works normally, first check for these problems.
- An intermittent short in the wire between the ECM (E29) and the data link connector (DLC).
- An intermittent short in the wire between the ECM (E31) and the gauge assembly.
- The readiness codes are not set. (This is indicated if the MIL blinks several times after you turn the ignition switch ON (II) and wait about 20 seconds.)
NO - If the MIL is always off, go to step 6. But if the MIL sometimes works normally, first check for these problems.
- A loose No.10 METER (7.5A) fuse in the under-dash fuse/relay box.
- A loose No.20 IG1 (50A) fuse in the under-hood fuse/relay box.
- A loose No.6 ECU (ECM) (15A) fuse in the under-hood fuse/relay box.
- A loose No.17 FUEL PUMP (15A) fuse in the under-dash fuse/relay box.
- A poor connection at ECM terminal E31.
- An intermittent open in the GRN/WHT wire between the ECM (E31) and the gauge assembly.
- An intermittent short in the wire between the ECM (A21) and the manifold absolute pressure (MAP) sensor.
- An intermittent short in the wire between the ECM (A20) and the throttle position (TP) sensor, exhaust gas recirculation (EGR) valve position sensor or engine oil pressure (EOP) sensor.
- An intermittent short in the wire between the ECM (ES) and the fuel tank pressure (FTP) sensor or brake booster pressure sensor.
- An intermittent short in the wire between the ECM (C17) and TCM (CVT model).
6. Check the low oil pressure indicator (with the ignition switch ON).
Is the low oil pressure indicator on?
YES - Go to step 9.
NO - Go to step 7.
7. Inspect the No.10 METER (7.5 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES - Go to step 8.
NO - Repair short in the wire between No.10 METER (7.5A) fuse and the gauge assembly. Also replace the No.10 METER (7.5A) fuse.
8. Inspect the No.20 IG1 (50A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES - Repair open in the wire between the No.20 IG1 (50A) fuse and the gauge assembly. If the wires are OK, test the ignition switch.
NO - Repair short in the wire between No.20 IG1 (5OA) fuse and the under-dash fuse/relay box. Also replace the No.20 IG1 (50A) fuse.
9. Try to start the engine.
Does the engine start?
YES - Go to step 10.
NO - Go to step 13.
10. Turn the ignition switch OFF.
11. Connect ECM connector terminal E31 to body ground with a jumper wire.
12. Turn the ignition switch ON (II).
Is the MIL on?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Check for an open in the wire between the ECM (E31) and the gauge assembly. Also check for a blown MIL bulb. If the wires and the bulb are OK, replace the gauge assembly.
13. Turn the ignition switch OFF.
14. Inspect the No.6 ECU (ECM) (15A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES - Go to step 22.
NO - Go to step 15.
15. Remove the blown No.6 ECU (ECM) (15A) fuse in the under-dash fuse/relay box.
16. Remove the glove box.
17. Remove PGM-FI main relay 1(A).
18. 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 No.6 ECU (ECM) (15A) fuse and PGM-FI main relay 1. Also replace the No.6 ECU (ECM) (15A) fuse.
NO - Go to step 19.
19. Disconnect each of the components or 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 connector A (31P)
- Each injector 2P connector
- Idle air control (IAC) valve 3P connector
- Cam position (CMP) sensor 3P connector
- Crankshaft position (CKP) sensor 3P connector
- Hot restart fan relay.
Is there continuity?
YES - Go to step 20.
NO - Replace the component that made the short to body ground go away when disconnected. If the item is the ECM, update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
Also replace the No.6 ECU (ECM) (15A) fuse.
20. Disconnect the connectors of all these components.
- PGM-FI main relay 2
- ECM connector A (31P)
- Injectors
- Idle air control (IAC) valve
- Cam position (CMP) sensor
- Crankshaft position (CKP) sensor
- Hot restart fan relay.
21. 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 No.6 ECU (ECM) (15A) fuse.
NO - Replace PGM-FI main relay 1. Also replace the No.6 ECU (ECM) (15A) fuse.
22. Inspect the No.17 FUEL PUMP (15A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES - Go to step 35.
NO - Go to step 23.
23. Remove the blown No.17 FUEL PUMP (15A) fuse in the under-dash fuse/relay box.
24. Wait for 1 minute. If the radiator fan is running, wait for 1 minute after the radiator fan stops.
25. Disconnect ECM connector E (31P).
26. Check for continuity between ECM connector terminal E9 and body ground.
Is there continuity?
YES - Go to step 27.
NO - Replace the No.17 FUEL PUMP (15A) fuse, and update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
27. Remove PGM-FI main relay 2 (A).
28. Check for continuity between ECM connector terminal E9 and body ground.
Is there continuity?
YES - Repair short in the wire between the No.17 FUEL PUMP (15A) fuse and the ECM (E9), or between the No.17 FUEL PUMP (15A) fuse and the PGM-FI main relay 2. Also replace the No.17 FUEL PUMP (15A) fuse.
NO - Go to step 29.
29. Remove the rear seat cushion.
30. Remove the access panel from the floor.
31. Disconnect the fuel pump 5P connector.
32. 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 33.
33. Reinstall PGM-FI main relay 2 (A).
34. 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.
35. Wait for 1 minute. If the radiator fan is running, wait for 1 minute after the radiator fan stop.
36. Disconnect ECM connector E (31P).
37. Turn the ignition switch ON (II).
38. Measure voltage between ECM connector terminal E9 and body ground.
Is there battery voltage?
YES - Go to step 39.
NO - Repair open in the wire between the No.17 FUEL PUMP (15A) fuse and the ECM (E9).