Throttle Position Sensor: Adjustments

Fig. 2 Harness Connector, Throttle Position Sensor (potentiometer) & Adjustment Screw Assembly:

To perform TPS adjustment procedure, diagnostic tester MS 1700 or equivalent is required.
1. Verify that throttle is completely opened when accelerator pedal is fully depressed.
2. Turn ignition switch to On position.
3. Check TPS input voltage using a suitable digital volt-ohmmeter as follows:
a. Insert negative lead of volt-ohmmeter into terminal C of TPS harness connector and positive lead into terminal B of harness connector, Fig. 2. Do not disconnect harness connector. Insert leads into end of connector and push inward to contact terminals.
b. Move throttle plate to wide open position and note voltage reading. Input voltage should be approximately 4.3 volts.
c. Return throttle plate to closed position.
d. Remove positive lead from harness connector terminal B and insert it into terminal A.
e. Move throttle plate to wide open position, then note and record voltage reading.
f. Output voltage should be approximately 3.5-4.5 % of the input voltage.
g. Return throttle plate to closed position and determine required TPS output voltage.
4. To determine required TPS output voltage, note example:
a. Recorded input voltage was 4.2 volts.
b. 4.2 volts X 4 percent, equals an output voltage of .168 volts.
c. 4.2 volts X .5 percent, equals an output voltage range variance of ±.021 volts.
d. Output voltage should be .147-.189 volts.
5. To adjust output voltage, proceed as follows:
a. Block throttle linkage in wide open position.
b. Loosen TPS adjustment screws.
c. Rotate TPS upward or downward to obtain required output voltage.
d. Tighten TPS screws and check voltage readings. Adjust if necessary.