Throttle Position Sensor: Testing and Inspection

THROTTLE POSITION SENSOR

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 5 V 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 as 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 transmission 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 is outside 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

Using Scan Tool

HARNESS INSPECTION





STEP 1. Check for continuity in the ground circuit.
- Throttle position sensor connector: Disconnected

OK: GO TO STEP 2
NG: Repair the harnesses. (A1 - 92)





STEP 2. Check for an open or short-circuit between the throttle position sensor and the engine control module.
- Throttle position sensor connector: Disconnected
- Engine control module connector: Disconnected
- All control module connectors, such as the ECM connector, which use throttle position sensor output: Disconnected

OK: GO TO STEP 3
NG: Repair the harnesses. (A3 - 84, A4 - 81)





STEP 3. Measure the applied voltage.
- Throttle position sensor connector: Disconnected
- Engine control module connector: Connected
- Ignition switch: ON

Voltage (V): 4.8 - 5.2

OK: STOP
NG: Replace the engine control module.

SENSOR INSPECTION





1. Disconnect the throttle position sensor connector.





2. Measure the resistance between terminal (1) (sensor ground) and terminal (4) (sensor power).

Standard value: 3.5-6.5 kohms

3. Connect a pointer type ohmmeter between terminal (1) (sensor ground) and terminal (3) (sensor output).
4. Open the throttle valve slowly from the idle position to the full open position and check that the resistance changes smoothly in proportion with the throttle valve opening angle.





5. If the resistance is outside the standard value, or fails to change smoothly, replace the throttle position sensor.

TPS installation torque: 2.0 Nm (1.5 ft.lbs.)