See Figures 1 and 2
The Throttle Position Sensor (TPS) is located on the throttle body and tells the computer when the engine is at idle, off-idle, or at Wide-Open Throttle (WOT). At idle, the computer cancels the spark advance. Idle speed is computer-controlled through the automatic idle speed motor.
To completely test this sensor and circuitry, you need the DRBII scan tool, or equivalent. This is a test of the sensor only. This test applies only to V6, V8 and V10 engines.
This test requires a digital voltmeter. The sensor must be checked on the vehicle with its 3-wire connector engaged to the sensor. The center terminal wire of the sensor connector is the output terminal.
- Remove the air cleaner housing.
- Attach the positive lead of the voltmeter to the center terminal of the sensor harness.
- Attach the negative lead of the voltmeter to a good ground.
- With the ignition key in the ON position and engine not running, check the sensor output voltage at the center terminal wire of the connector. Check this at idle (throttle plate closed) and at Wide Open Throttle (WOT). At idle, the sensor output voltage should be greater than 200 millivolts. At WOT, the sensor output voltage should be less than 4.8 volts. The output voltage should increase gradually as the throttle plate is slowly opened from idle to WOT.
- If the sensor does not meet specifications, replace it.
REMOVAL & INSTALLATION
See Figures 3, 4, 5 and 6
- Remove the air cleaner housing assembly.
- Unplug the TPS electrical connector, remove the two bolts
- Remove the TPS from the throttle body.
The throttle shaft end of the throttle body slides into the socket in the TPS. The TPS must be installed so it can be rotated a few degrees. If the sensor will not rotate, install the sensor with the throttle shaft on the other side of the socket tangs. The TPS will be under slight tension when rotated.
- Install the TPS and its retaining bolts, tightening them to 60 inch lbs. (7 Nm).
- Manually operate the throttle control lever to check for any binding of the TPS.
- Connect the wire and install the air cleaner assembly.