What is P0121 fault code? What is the explanation for the Throttle/Pedal Position Sensor “A” Circuit Range Performance Problem malfunction? How can I fix the P0121 fault code What are the symptoms and causes for the P0121 fault code
What is the P0121 fault code? What does it signify?
A P0121 code is an indication that your engine’s throttle position sensor (TP) is not working properly. As with other codes related to throttle position sensors, this could lead to serious problems and even cause your vehicle’s inability to start. Let’s examine the P0121 code, and any possible consequences.
A P0121 code is a way to indicate that you are a professional. “Throttle/Pedal position Sensor “A” Circuit Range/Performance Issue . The powertrain control unit (PCM/ECM) monitors operation of the TP sensors. The error code P0121 is set when the PCM detects the sensor operating outside of a predetermined range.
Some vehicles also allow the setting of the code to be made if the TP (or manifold absolutepressure (MAP) sensor signals are not in sync.
The throttle position sensor is used to measure the openness of the throttle blade. Older vehicles have one TP sensor while electronic throttle control (ETC), two. The sensor location is located on the throttle body.
The TP sensor data is used by the PCM to calculate functions like idle speed, fuel consumption, and automatic transmission shifting points. ETC vehicles also have the PCM (or any other control module) that uses data from TP sensors to control the throttle motor/ throttle blade. Two TP sensors are used in this type of system to prevent possible malfunctions.
Fault code P0121 can be very dangerous, especially for vehicles equipped with ETC. It causes the control module of the vehicle to go into fail mode or safety mode. This reduces vehicle speed and acceleration. You may not be allowed to use the vehicle in certain cases.
This code also refers the accelerator pedal position sensor. This code may be used to indicate that the accelerator pedal position (APP), sensor is malfunctioning instead of the TTP sensor. Vehicles equipped with the ETC system use a pair APP sensors to control the throttle motor and blade.
The PCM, powertrain control module, sends a 5 Volt signal to the throttle position sensor. An example of a general measurement is: idle = 0.5 Volts, full throttle = 4 Volts. The PCM will set a P0121 code if it detects that the throttle angle for a given RPM is greater or lesser than it should be.
Other fault codes that can be related to the TP circuit and sensor: P0122, PP0122, PP0123, & P0124
What Are the Possible Causes of P0121 Fault Codes?
P0121 fault codes can be caused by many factors. Below are some common causes:
- – Defective throttle position sensor
- – Wiring or connection problems in the TP sensor circuit
- – Problems with the throttle body
- – Issues with sensors other than MAP or MAF
- – Control module problems (Unlikely).
- – Defective APP sensor
- – Error in APP circuit
Note: There may be other codes in addition to P0121. The causes and symptoms could differ from the ones listed here.
What are the symptoms of P0121 Trouble code?
You may experience one or more of these symptoms when code P0121 has been set:
- – Illumination at the check engine lights
- – Hard starting the engine
- – Hesitation during acceleration
- – Engine stalling
- – Idle irregularity
- – Exhaust smoke during acceleration
- – The vehicle might enter fail mode, or safe mode. This is when the vehicle can only be driven at a very slow speed with minimal throttle restriction.
How do I fix the P0121 fault code?
- Check for loose or damaged connections and wires and have them repaired.
- – Data between circuits B and A of the TP sensors should be compared and checked.
- – Replacing your TP sensor
How Serious Is the P0121 Fault Coding?
You might experience various driving problems if the code P0121 causes your vehicle to go into malfunction mode. This could include a lack or acceleration, slow speeds, hesitation or jerking.
