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Closed Throttle Switch

NOTE: It is important that all testing be done with the idle speed control motor plunger in the fully extended position, as it would be after a normal engine shut down. If it is necessary to extend the motor plunger to test the switch, an ISC motor failure can be suspected. Refer to ISC motor test.
  1. With ignition on, test switch voltage at diagnostic connector D2 between pin 13 and pin 7 (ground). Voltage should be close to zero at closed throttle and greater than 2 volts at any position other than closed throttle.
  2. If the voltage is always zero, test for a short circuit to ground in the wiring harness or switch. Test for an open circuit between pin 20 of ECU connector J2 and throttle switch.
  3. If voltage is always more than 2 volts, test for an open circuit in the wiring harness between the ECU and switch connector. Check for open circuit between the switch connector and ground. Repair or replace wiring harness as needed.
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