Throttle Position Sensor (TPS) Inspection and Replacement

INSPECTION
PROCEDURE

1. The TPS is mounted on the throttle body and connected to the throttle valve shaft. Based on the signals received from the TPS, the PCM determines the exact current position of the throttle valve, which corresponds to the degree the driver depresses the accelerator pedal. A failed sensor may cause uncontrolled fuel injection and unstable engine idle. If a TPS malfunction occurs, code P0122 or P0123 is stored in the self-diagnostic memory (refer to Section On-Board Diagnostics (OBD) - Operating Principle and Diagnostic Trouble Codes).

2. Using a voltmeter, measure the reference voltage supplied to the sensor by the PCM. Disconnect the wiring harness from the sensor and connect the voltmeter probes to the REF (+) and GND (-) terminals of the connector. With the ignition on (do not start the engine), the meter should read approximately 5.0 V. No voltage indicates an open circuit in the PCM wiring or a faulty PCM.

3. Next, check the sensor signal voltage. With the engine off and the throttle valve fully closed, connect the voltmeter between the SIG (+) and GND (-) terminals of the TPS connector.

To connect the voltmeter to the back of the connector terminals, a straightened metal paper clip can be used. Gradually open the throttle valve while observing the voltmeter. With the throttle closed, the signal voltage should be 0.5 ÷ 1.5 V and gradually increase to 4.5 V at full throttle opening. If not, replace the TPS.
REPLACEMENT
PROCEDURE

The TPS is securely fastened to the throttle body and is replaced only as part of the complete assembly (refer to Section Fuel and Exhaust Systems).