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Home >> Acura >> 1999 >> 3.5RL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Circuit Check >> Malfunction Indicator Light (Mil) >> Malfunction Indicator Light (MIL) Stays Illuminated Or Illuminates After 2 Seconds

Malfunction Indicator Light (MIL) Stays Illuminated Or Illuminates After 2 Seconds

  1. If symptom is intermittent, check for:
    • Loose ECU fuse No. 6 (20-amp) located in underhood fuse/relay box.
    • Loose FUEL PUMP fuse No. 22 (20-amp) located in underdash fuse/relay box.
    • Intermittent short in Red wire between PCM 22-pin connector terminal No. 13 and service check connector.
    • An intermittent short between PCM 12 pin connector terminal No. 5 (Red wire) and SCS service check connector.
    • Intermittent open in Green/Black wire between PCM 22-pin connector terminal No. 22 and service check connector.
    • Intermittent short in Green/Red wire between PCM 26-pin connector terminal No. 7 and gauge assembly.
    • Intermittent short in Yellow/Red wire between PCM 22-pin connector terminal No. 10 and MAP sensor.
    • Intermittent short in Yellow/Blue wire between PCM 22-pin connector terminal No. 21 and TP sensor, EGR valve lift sensor, Fuel Tank Pressure Sensor (FTPS), and TCS control valve angle sensor (if equipped with TCS).
    • Faulty PGM-FI main relay.
    • Loose IG COIL fuse No. 25 (30-amp) in underdash fuse/relay box.

    Perform repairs as necessary and recheck MIL operation. If no problems are found, go to next step.

  2. Connect scan tool to DLC connector. Using scan tool, check for DTCs. Turn ignition on and read any stored DTCs. See RETRIEVING CODES  under SELF-DIAGNOSTIC SYSTEM. If DTCs are not present, go to next step. If DTCs are present, go to DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION  under SELF-DIAGNOSTIC SYSTEM. After identifying DTC, go to appropriate DTC.
  3. Turn ignition off. Connect SCS Service Connector Tool (0PAZ-0010100) to service check connector. See Figure . Turn ignition on. If MIL does not flash, indicating no DTCs, go to next step. If MIL flashes, indicating DTCs, repair open or short in Light Green wire between PCM 22-pin connector terminal No. 4 and DLC. Go to DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION  under SELF-DIAGNOSTIC SYSTEM. After identifying DTC, go to appropriate DTC test.
  4. Attempt to start engine. If engine starts, go to next step. If engine does not start, go to step  7 .
  5. Turn ignition off, and then turn ignition on. Measure voltage between ground and PCM 12-pin connector terminal No. 5 (Red wire). If about 5 volts is present, go to next step. If about 5 volts is not present, repair short to ground in Red wire between PCM 22-pin connector and service check connector. See WIRING DIAGRAMS article.
  6. Turn ignition off. Disconnect PCM 26-pin connector. Turn ignition on. If MIL illuminates, repair short to ground in Light Green wire between PCM 26-pin connector terminal No. 7 and MIL. If MIL does not illuminate, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  7. Check fuse No. 6 (20-amp) located in underdash fuse/relay box. If fuse is okay, go to next step. If fuse is open, repair short in Yellow/Black wire between ECU fuse and PGM-FI main relay. See WIRING DIAGRAMS article. Replace fuse.
  8. Inspect IG COIL fuse (30-amp) located in underdash fuse/relay box. On all models, if fuse is okay, go to next step. If fuse is open, repair short in Black/Yellow wire between fuse and PGM-FI main relay. See WIRING DIAGRAMS article. Replace fuse.
  9. Turn ignition on. While observing MIL, one at a time, disconnect 3-pin connectors from MAP sensor, TP sensor, EGR valve lift sensor, fuel pump pressure sensor and TCS control valve angle sensor (if equipped). If MIL stays illuminated, go to next step. If MIL goes out when a sensor is disconnected, replace sensor that caused MIL to go out.
  10. Turn ignition off. Disconnect PCM 22-pin connector. Using DVOM connected to ground, check for continuity at PCM 22-pin connector terminals No. 10 (Yellow/Red wire) and No. 21 (Yellow/Blue wire). If continuity is not present, go to step  12 . If continuity is present, go to next step.
  11. If continuity is present, repair short to ground in Yellow/Red wire between PCM connector and MAP sensor, or short to ground in Yellow/Blue wire between PCM connector and EGR valve lift sensor, TP sensor, fuel tank pressure sensor and, if equipped, TCS control valve angle sensor.
  12. Turn ignition on. Individually measure voltage between ground and PCM 26-pin connector terminal No. 13 (Yellow/Black wire) and PCM 16-pin connector terminal No. 1 (Yellow/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, check for poor connections or loose wires between PCM and PGM-FI main relay. If okay, repair open in Yellow/Black wire(s) between PCM and PGM-FI main relay. See WIRING DIAGRAMS article. Ensure PGM-FI main relay is okay. See SYSTEM & COMPONENT TESTING article.
  13. Turn ignition off. Reconnect all disconnected sensor connectors and PCM 22-pin connector. Turn ignition on. Measure voltage between ground and PCM 26-pin connector terminal No. 26 (Brown/Black wire) and PCM 16-pin connector terminal No. 9 (Brown/Black wire). If one volt or more is present at either wire, repair open in Brown/Black wire(s) between PCM connectors and G101 ground. See WIRING DIAGRAMS article. If less than one volt is present at both wires, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
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