Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is getting confusing signals from the sensor that tells it how much you're pressing the gas pedal. It's like if your game controller was sending mixed signals to your console.
The P0121 code is triggered when the Powertrain Control Module (PCM) detects that the Throttle Position Sensor (TPS) is not operating within the expected range, or it is not performing as expected.
The Throttle Position Sensor (TPS) is a sensor used to monitor the position of the throttle in an internal combustion engine. It consists of a variable resistor that changes its resistance as the throttle moves. The PCM uses this information to determine engine load and adjust fuel delivery and ignition timing. A P0121 code indicates that the TPS signal is out of the predetermined range or is inconsistent with the expected values.
• Check Engine Light is on
• Poor engine performance
• Hesitation or stalling
• Faulty Throttle Position Sensor
• Wiring issues (short or open circuit)
• Faulty PCM
PCM: Powertrain Control Module
TPS: Throttle Position Sensor
• Use an OBD-II scanner to confirm the code
• Inspect the wiring and connections to the TPS
• Test the TPS with a multimeter
• Replace the Throttle Position Sensor
• Repair or replace damaged wiring
• Reprogram or replace the PCM if necessary
• OBD-II scanner
• Multimeter
• Screwdriver set
$100 - $300
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect and clean the throttle body
• Ensure proper maintenance of electrical connections
• Use quality fuel to prevent sensor contamination
Sensor Issue
• Do not ignore the Check Engine Light
• Have the vehicle inspected by a professional
• Avoid driving at high speeds until the issue is fixed
Check with your vehicle manufacturer for specific warranty coverage on emission-related components.
The P0121 code has been common since the introduction of electronic throttle control systems in vehicles, which began in the late 1990s.
Moderate – While the vehicle may still be drivable, it can lead to poor performance and increased fuel consumption.
Driving with an unresolved P0121 code can lead to increased emissions, which may not comply with local environmental regulations.
• Engine at operating temperature
• Throttle pedal pressed
The Throttle Position Sensor is typically located on the throttle body, which is attached to the intake manifold.
Q: Can I drive my car with a P0121 code?
A: You can drive your car, but it's not recommended as it may lead to poor performance and increased fuel consumption.
Q: How do I reset the P0121 code?
A: You can reset the code using an OBD-II scanner, but it's important to fix the underlying issue first.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.