P0122 Honda: Complete Guide on Diagnosis, Testing, and Replacement Procedures

Today, we’ll be focusing on the throttle position sensor commonly found in the throttle body of modern vehicles. I’ll demonstrate two techniques for testing this sensor, one using a scan tool and the other without the scan tool.

If you’ve been following my videos, this will likely be the last sensor video before I complete the job on the S2000 behind me.

Using a Scan Tool

The first technique involves using a scan tool. You only need to find your vehicle’s port and have a scan tool that can read data stream. This method is convenient and quick, making it easy to detect potential issues.

With the scan tool, you can easily navigate through the menu to find the throttle position sensor and observe changes in its value as you manipulate the accelerator. Any anomalies in the readings could indicate a problem with the sensor or wiring.

Old-Fashioned Testing

If you don’t have a scan tool, an alternative method involves testing the sensor with a digital multimeter. By disconnecting the sensor’s harness connector and using the multimeter to measure resistance or ohms, you can assess the sensor’s functionality.

Additionally, you can verify if the sensor is receiving power by testing the harness connector with a multimeter set to volts DC. This helps in identifying potential wiring issues.

Replacement Procedure

If the sensor needs replacement, it’s essential to ensure that power is reaching the harness connector. If the sensor is faulty, replacing the entire throttle body might be necessary, especially in modern vehicles where the sensor is integral to the throttle body.

Replacing the throttle body involves disconnecting various components, removing fasteners holding the throttle body to the intake manifold, and installing a new throttle body with a gasket. Performing an idle reset after replacement is also crucial.


Testing and replacing the throttle position sensor is a manageable task that can be done at home with the right tools. By following these simple steps, you can potentially save money and keep your vehicle running smoothly.

Thank you for watching!

What is the throttle position sensor?

The throttle position sensor is built into the throttle body on many modern vehicles. It measures the position of the throttle and plays a crucial role in the functioning of the vehicle’s engine.

How to test the throttle position sensor with a scan tool?

Using a scan tool, one can access the data stream and locate the throttle position sensor. By observing the value displayed and checking for changes as the accelerator is pressed, one can test the functionality of the sensor.

How to test the throttle position sensor without a scan tool?

By using a digital multimeter, the resistance or ohms test can be performed directly on the terminals of the throttle position sensor. The values should change as the throttle is manipulated, indicating proper functionality. Additionally, one can verify the power supply to the sensor using a multimeter and a paper clip to test the harness connector.

What to do if the throttle position sensor test shows irregular readings?

Irregular readings may indicate a faulty sensor or a wiring problem. If power supply to the sensor is verified and the readings are still abnormal, it may be necessary to replace the throttle body, which involves disconnecting various components and installing a new throttle body with a gasket.

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