Throttle Position Sensor: Testing and Inspection

Throttle Position Sensor Circuit:

To test the Throttle Position Sensor, located on the throttle body, proceed as follows.


COMPONENT TEST
1. Disconnect the throttle position sensor connector.

2. Measure the resistance between terminals 1 and 2 of the throttle position sensor connector.
Terminal 1: Sensor power
Terminal 2: Sensor ground

Standard Value
3.5k - 6.5k ohm

3. Connect an analog type ohmmeter between terminals 2 and 4.
Terminal 2: Sensor ground
Terminal 4: Sensor output

4. Slowly open the throttle valve from the idle position to the fully open position and check that the resistance values change smoothly with the opening of the throttle valve.

Standard Value
0.5k ohm increasing to 3.5k - 6.5k ohm

5. If the resistance is out of specification, or if the change is not smooth, replace the throttle position sensor.

HARNESS TEST
1. Disconnect the TPS connector and turn the key to the ON position.
2. Using a voltmeter, measure the supply voltage between the TPS harness connector terminal 1 and ground.

Voltage:
4.8 - 5.2 Volts.

3. Check for continuity between the TPS harness connector terminal 2 and ground.

Continuity:
Should exist.

4. Turn the key to the OFF position. Disconnect the negative battery terminal and the ECM connector. Check for continuity between the ECM harness connector terminal 14 and ground. Check for continuity between the TPS harness connector terminal 4 and ground.

Continuity:
Should not exist.

5. Check for continuity between the ECM harness connector terminal 19 and the TPS harness connector terminal 2.

Continuity:
Should exist.

If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, clear the trouble codes and road test the vehicle to confirm that the repair has corrected the problem and the code doesn't return.

If the same trouble code reoccurs, it is possible that there is an intermittent failure of the component or the ECM. Check for looseness at all harness junctions and test for an intermittent failure.