Throttle Position Sensor: Adjustments

IDLE AND FULL THROTTLE SWITCH VOLTAGE SUPPLY CHECK

Idle And Full Throttle Switch Harness Connector:

1. Disconnect harness connector to idle and full throttle switch on throttle body (arrow).

Harness Connector Terminal I.D.:

2. Turn ignition switch ON and check voltage between terminal 2 of harness connector and engine ground.

- Should be 12 VOLTS.

- If not, check for open circuit between terminal 2 and fuse relay panel.

3. Turn ignition switch OFF.

IDLE SWITCH CHECKING AND ADJUSTING

Throttle Switch Connector I.D.:

1. With throttle closed connect ohmmeter between terminal 1 and terminal 2 of switch connector.

- Reading should be 0 OHMS (switch closed).

Idle Switch Adjustment:

2. Install a 0.020 in. (0.5 mm) feeler gauge between throttle valve stop and throttle stop adjustment screw.

- Reading should be 0 OHMS (switch closed).

3. Open throttle valve slowly.

- Resistance should change from zero ohms (idle switch closed) to infinite ohms (idle switch open) as soon as throttle lever is moved, then go back to zero ohms when throttle is closed.

4. Loosen idle switch screws and adjust position of idle switch to obtain above readings if necessary.

FULL THROTTLE SWITCH CHECKING AND ADJUSTING

Full Throttle Switch Adjustment:

1. Screw protractor 3084 (or equivalent) onto throttle shaft, (unscrew nut on throttle shaft if necessary).
2. Fasten pointer for protractor to throttle cable using rubber band (arrow).
3. Push throttle lever to full open (wide open throttle) and zero pointer to protractor disc. Close throttle and check protractor operation.

Throttle Switch Connector I.D.:

4. Connect ohmmeter between terminals 3 and 2 of throttle switch connector (throttle valve closed).

- Resistance should be INFINITE OHMS (switch open).

5. Slowly open throttle valve all the way (full throttle) while watching protractor and ohmmeter readings.

- Resistance should remain infinite ohms (switch open) then go to 0 OHMS (switch closed) when throttle is within approx. 10° of full throttle stop.

6. Loosen full throttle switch screws and adjust position of switch to obtain above readings if necessary.

Harness Connector Terminal I.D.:

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

7. 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 harness connector terminal 1 and fuel control unit terminal 28.

b. Open or grounded circuit between throttle switch harness connector terminal 1 and ignition control unit terminal 7.

c. Open or grounded circuit between throttle switch harness connector terminal 3 and fuel control unit terminal 31.

d. Open or grounded circuit between throttle switch harness connector terminal 3 and ignition control unit terminal 9.