Throttle Position (TP) Sensor Adjust

Fig. 24 Throttle Position Sensor (TPS) adjustment screw plug removal:

DO NOT ADJUST TPS UNLESS IDLE SPEED IS WITHIN SPECIFICATIONS

1. Remove air cleaner assembly and connect "scan" tool to ALDL connector. Set "scan" to display TPS voltage.

2. Retract ILC plunger using a vacuum pump until throttle lever contacts idle stop screw. If ILC will not retract see Chart C-2C.

3. With ignition on and ignition off TPS voltage should read between .2 and .7 volts. If so no adjustment is necessary. If less than .2 volts see trouble code 22. If more than 2.5 volts see trouble code 21. If between .7 and 2.5 volts proceed with next step.

4. Remove TPS plug by drilling a 5/64" (.2mm) hole 1/16" to 1/8" deep, then install a No. 8 x 1/2" self tapping screw and pry plug out. NOTE: A new plug must be installed to keep the adjustment screw from turning and discourage unneeded adjustment. If a new plug cannot be installed because casting is damaged a replacement screw is available with locking compound and doesn't require the use of a plug.

5. With vacuum still applied to ILC use tool J 28696 or BT 7967A (or equivalent) turn adjusting screw until a voltage reading of .41 +/- .1 volts is obtained. Replace TPS if voltage cannot be adjusted to this range.

6. Replace plug and clear trouble code memory.