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Home › Acura › 2000 › 3.2TL › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Circuit Check › Malfunction Indicator Light (Mil)

Malfunction Indicator Light (Mil)

  1. Turn ignition on and observe Malfunction Indicator Light (MIL). If MIL always comes on and stays on, go to step  8. If MIL does not come on and stay on, go to next step. If MIL sometimes operates normally, check for an intermittent short circuit in Brown wire between 32-pin PCM connector terminal No. 10 and DLC, check for an intermittent open circuit in Gray wire between 32-pin PCM connector terminal No. 21 and DLC, and also check for an intermittent short circuit in Green/Orange wire between 32-pin PCM connector terminal No. 18 and gauge assembly. Repair wiring as necessary.
  2. If MIL is always off, go to next step. If MIL sometimes operates normally, check for the following:
    • Loose No. 9 BACK-UP LIGHT, INSTRUMENT LIGHT (7.5-amp) fuse in underdash fuse/relay box.
    • Loose ACG S (15-amp) fuse in underhood fuse/relay box.
    • Loose No. 1 FUEL PUMP (15-amp) fuse in underdash fuse/relay box.
    • Intermittent connection at PCM 32-pin connector terminal No. 18 (Green/Orange wire).
    • Intermittent open circuit in Green/Orange wire between PCM 32-pin connector terminal No. 18 and gauge assembly.
    • Intermittent short circuit in Yellow/Red wire between PCM 31-pin connector terminal No. 19 and MAP sensor.
    • Intermittent short circuit in Yellow/Blue wire between PCM 31-pin connector terminal No. 28 and TP sensor, EGR valve lift sensor, and fuel tank pressure sensor.
  3. Turn ignition off, then on. If oil pressure light is on, go to next step. If oil pressure light is not on, check for a blown No. 9 BACK-UP LIGHT, INSTRUMENT LIGHT 7.5-amp fuse in underdash fuse/relay box. Also check for short or open circuit in Yellow wire between No. 9 BACK-UP LIGHT, INSTRUMENT LIGHT 7.5-amp fuse and gauge assembly.
  4. Attempt to start engine. If engine does not start, go to next step. If engine starts, turn ignition off. Connect jumper wire between 32-pin PCM connector terminal No. 18 (Green/Orange wire) and ground. Turn ignition on. If MIL comes on, replace PCM. If MIL does not come on, check for an open circuit in Green/Orange wire between 32-pin PCM connector terminal No. 18 and gauge assembly.
  5. Turn ignition off. Disconnect PCM 31-pin connector. Measure continuity between PCM 31-pin connector terminal No. 28 (Yellow/Blue wire) and ground, and between terminal No. 19 (Yellow/Red wire) and ground. If continuity is not present, go to next step. If continuity is present, disconnect 3-pin connector from MAP sensor, EGR valve lift sensor, fuel tank pressure sensor, TP sensor, mainshaft speed sensor, and countershaft speed sensor one at a time. Check individually for continuity between ground and PCM 31-pin connector terminal No. 19 (Yellow/Red wire) and terminal No. 28 (Yellow/Blue wire). If continuity is present, repair wiring for a short circuit to ground. If continuity is not present, replace appropriate sensor.
  6. Disconnect fuel injector and IAC valve connectors. Turn ignition on. Measure voltage between ground and PCM 25-pin connector terminal No. 1 (Yellow/Black wire) and terminal No. 9 (Yellow/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, check for an open circuit in Yellow/Black wire, poor connection at PGM-FI main relay, or defective PGM-FI main relay. Repair as necessary.
  7. Reconnect sensor connectors, then reconnect PCM 31-pin connector. Turn ignition on. Measure voltage between ground and PCM 25-pin connector terminal No. 2 (Black wire), No. 10 (Black wire) No. 20 (Brown/Yellow wire), and No. 22 (Brown/Yellow wire). If less than one volt is present, replace PCM. If one volt or more is present, repair open circuit in appropriate wiring between ground and PCM.
  8. Connect scan tool to DLC. Turn ignition on. Check for DTCs. If any DTCs are present, diagnose as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  table. If DTCs are not present, turn ignition off. Disconnect PCM 32-pin connector. Measure continuity between ground and DLC 16-pin connector terminal No. 15 (Gray wire). If continuity is not present, go to next step. If continuity is present, repair short circuit in Gray wire between DLC terminal No. 15 and PCM 32-pin connector terminal No. 21.
  9. Measure continuity of Gray wire between PCM 32-pin connector terminal No. 21 and DLC 16-pin connector terminal No. 15. If continuity is present, go to next step. If continuity is not present, repair open circuit in Gray wire between DLC and PCM.
  10. Turn ignition off, then on. Measure voltage between PCM 32-pin connector terminal No. 10 (Brown wire) and ground. If about 5 volts are present, go to next step. If about 5 volts are not present, repair short circuit in wiring between DLC and PCM.
  11. Turn ignition off. Disconnect PCM 32-pin connector. Turn ignition on. If MIL comes on, repair short circuit in Brown wire between PCM and gauge assembly. If MIL does not come on, replace PCM.
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