Throttle Position Sensor (TPS)

Throttle Position Sensor Circuit:

Operation

The throttle-position sensor functions to convert the degree of opening of the throttle valve to Voltage, and to input that Voltage (as signals) to the engine control module. The engine control module, based upon those signals, then regulates the amount of fuel injection, etc.

The 5V power supply within the engine control module is supplied to the throttle-position sensor, after which it passes through the resistance within the sensor and is grounded at the engine control module.

When the throttle valve shaft is rotated all the way from the idling position to the fully open position, the resistance between the throttle position sensor's variable-resistance terminal and the ground terminal also increases in accordance with that rotation, and, as a result, the Voltage of the throttle-position sensor's variable-resistance terminal also becomes higher in accordance with that rotation.


Troubleshooting Hints

Hint 1: The signals of the throttle-position sensor are more important for control of the automatic transaxle than for control of the engine; shifting "impact shocks" are produced if there is a malfunction of the throttle-position sensor.

Hint 2: If the Voltage of the throttle position sensor deviates from the standard value, check once again after making the throttle position sensor adjustment. In addition, if there are any indications that the fixed SAS has been moved, adjust the fixed SAS.





Inspection






Harness Inspection


COMPONENT TEST
1. Disconnect the throttle position sensor connector.

2. Measure the resistance between terminals 1 and 4 of the throttle position sensor connector.
Terminal 1: Sensor power
Terminal 4: Sensor ground

Standard Value
3.5k - 6.5k Ohm

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




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 ECU. Check for looseness at all harness junctions and test for an intermittent failure.