Throttle Full Open Switch: Testing and Inspection

Wide Open Throttle Switch:

1. The ignition switch should be in the OFF position. Disconnect the electrical connector from the wiring harness, and test the on-off operation of the switch with a high impedance digital volt-ohm meter (DVOM). Test the switch several times by manually operating the throttle lever. When the throttle lever is rotated to full throttle position, a low resistance should be indicated on the DVOM. When the throttle lever is returned to idle, the DVOM should indicate an infinite resistance value. Replace the WOT if resistances are not correct.

Diagnostic Connector Identification:

2. Connect the WOT electrical connector to the wiring harness connector. Turn the ignition switch ON (engine not running), and connect a voltmeter across diagnostic connector 2 (D2) pins 6 and 7 (ground). There should be 0 volts when the throttle lever is in the WOT position. There should be 2 or more volts when the throttle lever is at any position except WOT.
3. If there are no voltage readings in any throttle lever positions, check for a short to ground in the wire harness or switch. Repair wiring harness as needed.
4. If there are no voltage readings and no shorts to ground, check for an open circuit in the wiring harness by connecting an ohmmeter across ECU electrical connector terminal 8 and the WOT switch connector. If the ohmmeter indicates continuity, then the harness is OK. If the ohmmeter indicates infinity, then there is an open in the wiring harness that needs to be repaired.
5. If the voltage reading from step 2 is always greater than 2 volts, no matter what the throttle lever position, then there is an open circuit between the WOT switch and ground. Repair wiring harness as necessary.