P0120 Lexus Code - Throttle / Pedal Position Sensor / Switch 'A' Circuit Malfunction
Quick Answer
The throttle position sensor is mounted on the throttle with motor body assembly and detects the opening angle of the throttle valve. Common causes include Faulty Throttle Position Sensor (built into Throttle Body Assembly), Throttle Position Sensor circuit is open or shorted, Throttle Position Sensor poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0120 Lexus indicates Throttle / Pedal Position Sensor / Switch 'A' Circuit Malfunction.
- Common causes
- Common causes include Faulty Throttle Position Sensor (built into Throttle Body Assembly), Throttle Position Sensor circuit is open or shorted, Throttle Position Sensor poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0120 Lexus Description
As the valve closes, the sensor output voltage decreases and as the valve opens, the sensor output voltage increases. The Engine Control Module (ECM) calculates the throttle valve opening angle according to these signals and controls the throttle actuator in response to driver inputs. These signals are also used in calculations such as air-fuel ratio correction, power increase correction, and fuel-cut control.
The ECM uses the throttle position sensor to monitor the throttle valve opening angle. There are several checks that the ECM performs to confirm the proper operation of the throttle position sensor.
This sensor transmits two signals, if the output voltage difference between the two signals deviates from the normal operating range, the ECM interprets this as a malfunction in the throttle position sensor. The ECM illuminates the MIL and stores the Diagnostic Trouble Code (DTC).
What are the Possible Causes of the DTC P0120 Lexus?
- Faulty Throttle Position Sensor (built into Throttle Body Assembly)
- Throttle Position Sensor circuit is open or shorted
- Throttle Position Sensor poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P0120 Lexus?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0120 Lexus code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0120 Lexus Code
No Frequently Asked Questions about P0120 Lexus Code found.
Discuss the causes and fixes for P0120 Lexus OBDII Code
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I have a 1998 Lexus GS300 that i drove to work parked for lunch came out to go home would turn over but would not start. Used by scantool got two code P0120 and P1120 have you seen this issue before?
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