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Home › Mitsubishi › 1996 › Eclipse Base, Standard › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes - 2.0L Turbo › Circuit Tests › DTC P0505 - Idle Control System Malfunction

DTC P0505 - Idle Control System Malfunction

NOTE: For component terminal identification, see TERMINAL IDENTIFICATION  in this article. For wiring diagrams, see WIRING DIAGRAMS - 2.0L TURBO article.
  1. Ensure Engine Coolant Temperature (ECT) is below 68°F (20°C). Using a stethoscope, listen for operating sound of Idle Air Control (IAC) motor when ignition switch is placed in ON position. If operating sound can be heard, go to next step. If no operating sound can be heard, check IAC motor. See IDLE AIR CONTROL (IAC) MOTOR in SYSTEM/COMPONENT TESTS - 2.0L TURBO article.
  2. On non-turbo engine, go to step 5). Disconnect IAC motor connector. Turn ignition on. Check voltage between ground and IAC motor connector terminal No. 2 (Red wire), and between ground and terminal No. 5 (Red wire). If battery voltage exists, go to next step. If battery voltage does not exist, check wiring harness between MFI relay and IAC motor connector.
  3. Disconnect PCM connector. Turn ignition on. Check voltage between ground and PCM terminals No. 4 (Gray wire), No. 5 (Gray/Blue wire), No. 17 (Green/Black wire) and No. 18 (Green/Yellow wire). If battery voltage exists, check PCM connector. If PCM connector is okay, replace PCM.
  4. If battery voltage does not exist, check IAC motor connector and wiring harness between PCM and IAC motor connector. If connector and wiring are okay, replace PCM.
  5. Turn ignition off. Connect Test Harness (MB991348 ) between IAC motor and connector. Check voltage between ground and test harness terminals No. 2 (Black clip) and No. 4 (White clip). Voltage should momentarily go from 1.5-4.0 volts to less than one volt or more than 4.5 volts right after ignition switch is turned on. If voltage is as specified on both circuits, replace PCM. If voltage is not as specified, go to next step.
  6. Disconnect IAC motor connector. Check voltage between ground and IAC motor connector terminals No. 1 (Green/Yellow wire), No. 2 (Gray/Blue wire) and No. 4 (Green/Yellow wire). Voltage should be 4.8-5.2 volts. Check continuity between ground and IAC motor connector terminal No. 3 (Black wire). Go to next step.
  7. If voltage is as specified and continuity exists, check IAC motor connector. If IAC motor connector is okay, replace IAC motor valve position sensor. If voltage is not as specified or continuity does not exist, check IAC motor connector and wiring harness between PCM and IAC motor connector. If connector and wiring are okay, replace PCM.
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