Throttle Full Close Switch: Testing and Inspection

CIS-E III Control Unit Harness Connectors (Pin # Locations):

1. Disconnect throttle switch connector at throttle body, and check voltage between terminal #2 of harness side of connector and ground.
- Should have battery voltage. If not, check for open circuit between terminal #2 and fuse relay panel.

2. Connect ohmmeter between terminals #1 and #2 of switch side of connector.

3. Open throttle about half way and close slowly, while observing the resistance.
- Resistance should be infinite (idle switch open) while throttle is open and then go to zero (idle switch closed) when throttle stop is within approx. 0.7mm (0.028") of idle stop adjustment screw. Adjust position of idle switch if necessary.

4. Connect ohmmeter between terminals #3 and #2 of switch side of connector.
- Resistance should be infinite (open circuit).

5. Slowly open throttle all the way.
- Resistance should remain infinite and then go to zero when throttle is within approx. 10~ of full throttle stop.

If codes 2121 &/or 2123 were displayed and no problems have been found up to this point, check for.

a. Open or grounded circuit between throttle switch connector terminal #1 and fuel control unit terminal #28.
b. Open or grounded circuit between throttle switch connector terminal #3 and fuel control unit terminal #31.
c. Grounded circuit between fuel control unit terminals #28 and #31, and ignition control unit terminals #7 and #9 respectively.