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Home >> Acura >> 1993 >> Legend Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Trouble Codes >> Code 0 Or No Codes >> MIL Stays On
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

MIL Stays On

  1. Check ECM for fault codes. See RETRIEVING CODES  under SELF-DIAGNOSTIC SYSTEM. Service codes as necessary. If no codes are present, remove jumper wire from self-diagnostic connector. Start engine. If engine does not start, go to step 6. If engine starts, turn ignition off. Connect ECM Test Harness (07LAJ-PT3010A ) between ECM and ECM connectors. See Figure .
  2. Turn ignition on. Measure voltage between terminals C9 (+) and A26 (-) of ECM connectors. If about 5 volts are present, go to next step. If voltage is not about 5 volts, repair short to body ground in White wire between ECM terminal C9 and self-diagnostic connector.
  3. Connect jumper wire to self-diagnostic connector. If about 5 volts are now present, check for open in White wire between self-diagnostic connector and ECM. Check for open in Black wire between self-diagnostic connector and ground.
  4. If about 5 volts are not present, remove jumper wire from self-diagnostic connector. Turn ignition off. Disconnect connector "A" of ECM. Turn ignition on. If MIL is on, repair short to ground in Blue wire between terminal A13 and instrument cluster. See Figure .
  5. If MIL is not on, replace ECM and retest.
  6. If engine did not start, check fuses No. 5 (20-amp) and IG COIL (30-amp) in underdash fuse box. Replace bad fuses. Turn ignition on. Install jumper wire between self-diagnostic connector terminals. Individually disconnect 3-pin connectors on MAP and EGR valve lift sensors.
  7. If MIL goes out, replace sensor causing MIL to go out. If MIL is on, connect jumper wire to self-diagnostic connector. Disconnect throttle position sensor or ignition timing adjuster connector. Check to see if ECM flashes Code 7 or 18. If Code 7 is indicated, replace throttle position sensor. If Code 18 is indicated, replace ignition timing adjuster.
  8. If Code 7 or 18 is not indicated, turn ignition off. Remove jumper wire. Connect ECM Test Harness (07LAJ-PT3010A ) between ECM and ECM connectors. See Figure . Disconnect connector "D" from ECM side only. Individually check for continuity between body ground and terminals D19 and D20.
  9. If continuity exists, repair short to ground in Yellow/White wire between ECM terminal D19 or D20 and MAP sensor, ignition timing adjuster, throttle position sensor or EGR valve lift sensor.
  10. If continuity does not exist, reconnect connector "D". Reconnect all sensor connectors. Turn ignition on. Individually measure voltage between ECM body ground and terminals A26 and B2. See Figure . If voltage is more than one volt, repair open in Brown/Black wire (A26) or Brown/Black wire (B2) between affected terminal and ground G101 at intake manifold. See Figure .
  11. If voltage was less than one volt, individually measure voltage between ECM terminal A26 (-) and terminals C1 (+) and A25 (+). See Figure . If battery voltage is present, turn ignition off, replace ECM and retest. If battery voltage is not present, repair open in Yellow/Black wire circuit between main relay and ECM terminals A25 and C1. If circuit is okay, check main relay and connector.
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