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Home >> Mitsubishi >> 1994 >> Eclipse Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Tests >> Code 15: Idle Speed Control Position Sensor
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Code 15: Idle Speed Control Position Sensor

NOTE: For component terminal identification, see TERMINAL IDENTIFICATION  . For wiring diagrams, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section.
  1. If using scan tester, go to step 3). Disconnect Idle Speed Control (ISC) motor position sensor connector. Using DVOM, check resistance between ISC motor position sensor terminals No. 2 and No. 3. If resistance is not 4000-6000 ohms, replace ISC motor position sensor. If resistance is as specified, go to next step.
    CAUTION: Apply only 6 volts DC or less to ISC motor connector. Higher voltage could cause servo gears to lock up.
  2. Disconnect ISC motor connector. Connect a 6-volt DC power supply between ISC motor connector terminals No. 1 and No. 2 to operate ISC motor. Check resistance between ISC motor position sensor terminals No. 3 and No. 5. Ensure ISC motor position sensor resistance changes smoothly as motor extends and retracts. If resistance does not change smoothly, replace ISC motor assembly. If resistance changes smoothly, go to step 4).
  3. Ensure engine coolant temperature is 185-205°F (85-95°C). Place transmission in Park or Neutral. Turn off all accessories except A/C. Ensure A/C clutch is operating when A/C system is on. With engine at idle, use scan tester to read Idle Speed Control (ISC) motor position sensor voltage. See ISC VOLTAGE SPECIFICATIONS  table. If voltage is not as specified, replace IAC motor position sensor. If voltage is as specified, go to next step.
    ISC VOLTAGE SPECIFICATIONS

    Application A/C Switch Position Standard Voltage
    All Models Off .5-1.3
    On .8-1.8
    (1) .9-1.9
    (1) On A/T models only, apply brakes, place transmission selector in "D" position and A/C switch in ON position.
  4. Disconnect ISC motor position sensor connector. Turn ignition switch to ON position. Using DVOM, check voltage between chassis ground and sensor connector terminal No. 2. Check voltage between chassis ground and sensor connector terminal No. 6. Voltage should be 4.8-5.2 volts on both circuits. If voltage is not as specified, repair appropriate wiring harness circuit(s) as necessary. If voltage is as specified, go to next step.
  5. Check for continuity between chassis ground and sensor connector terminal No. 3. If continuity does not exist, repair wiring harness as necessary. If continuity exists, condition required to set trouble code is not present at this time. Test is complete. Intermittent problem may exist. See TESTS W/O CODES article in the ENGINE PERFORMANCE Section.
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