Q: brake pedal position sensor malfunction came up as a code PO120 since the check engine light was on my 2002 Lexus GS300.

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The car was running fine and I pushed the brake and stopped at a stop sign and it started sputtering and the check engine like was on. There I had it read it stated PO120 TPS/ Brake Pedal Circuit Sensor Malfunction. Once reset it ran good again until I applied the brake once again it started sputtering and had no power.

My car has 10700 miles.
My car has an automatic transmission.

Trouble code P0120 relates primarily to malfunctions in the throttle position sensor, located in the throttle body, and/or circuitry and wiring to the sensor. Standard practice is to measure the voltage leaving the sensor at various throttle plate angles (the sensor is a potentiometer) and compare those values to factory specs. That is performed using an automotive scan tool and the problem is usually quickly pinpointed. If the voltage irregularity is marked, a standard multimeter might be sufficient for measuring as well. If you want a speedy diagnostic and resolution of this, please request a check engine light diagnostic and the responding certified mechanic will get this resolved for you, right at your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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