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Code 24: Idle Air Control Solenoid Valve

NOTE: Refer to illustration for ECU connector and terminal identification. See Figure .
  1. With engine warm and idling, measure voltage between ECU connector E29, terminal No. 2 (backprobe) and ground, then measure voltage between ECU connector E29, terminal No. 1 and ground. Voltage should be less than one volt on one terminal and greater than 13 volts on the other. Voltage readings may switch if ECU tries to regulate idle speed while testing. If voltage readings are are correct, repair ECU harness connector or replace ECU. If indicated voltage readings are not present, go to next step.
  2. Turn ignition off. Disconnect IAC connector. Measure resistance between IAC valve terminals No. 1 and 2, and between terminals No. 2 and 3. If 32 ohms are present, go to next step. If 32 ohms are not present, replace IAC solenoid valve.
  3. Turn ignition on. Measure voltage between IAC connector terminal No. 2 (Yellow/Red wire) and ground. If minimum 10 volts are present, repair or replace connector between ECU and IAC valve. If minimum of 10 volts are not present, repair or replace harness connector.
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