Understanding trouble codes and how they work can be confusing for many, as there are multiple possible causes and symptoms. Code P0124 indicates a potential problem with the throttle/pedal position sensor “A” or its circuit. Learn more about why this code sets and what signs to look out for with this brief guide.
What Does the P0124 Code Mean?
Diagnostic trouble code (DTC) P0124 stands for “Throttle/Pedal Position Sensor “A” Intermittent.” This code sets when the powertrain control module (PCM) detects a certain number of erratic or intermittent signals from the “A” throttle position sensor (TPS) or pedal position switch (PPS) circuit over a set period of time and under a specific set of circumstances. The PCM may also set this code if it determines that the signal coming from the TPS or PPS is unreliable.
Note: The definition of code P0124 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.
The throttle position sensor can be found on the throttle body of the intake manifold. Meanwhile, the pedal position switch is usually part of the accelerator pedal assembly. Both of these sensors detect the force of the driver’s foot and provide precise input about the power needed from the engine and how urgently this power is needed.
The PCM uses the input voltage from the throttle position sensor to manage the air-fuel ratio and spark timing. The data from the throttle position sensor may also be used to monitor intake air flow, exhaust oxygen content, exhaust gas recirculation (EGR), engine load percentage, and other emissions system components. In a drive-by-wire system, the throttle position sensor also sends feedback voltage to verify if the desired throttle body opening has been achieved.
Meanwhile, the pedal position switch can be found on vehicles equipped that use an electronic throttle body or a drive-by-wire system. In these systems, the movement of the driver’s foot is translated by the pedal position switch into a falling or rising voltage. This voltage signal is sent to the PCM, which uses it to control the opening and closing of the electronic throttle body, the air-fuel ratio, ignition spark timing, and other components in the emissions system.
Since the throttle position sensor and the pedal position switch are vital to the engine and your car’s drivability, this trouble code should be addressed immediately.
What Are the Possible Causes of the P0124 Code?
Like many diagnostic trouble codes, the P0124 code has a handful of possible causes. Listed below are some of the probable reasons why a P0124 code may set:
- Defective or misadjusted throttle position sensor
- Faulty pedal position sensor
- Open, shorted, or high resistance throttle position or pedal position sensor sensor “A” circuit
- Damaged throttle body
- Faulty PCM
- PCM programming error
- Dirty, carbon-filled throttle bore
What Are the Common Symptoms of the P0124 Code?
For many diagnostic trouble codes, the only noticeable symptom is an illuminated check engine light. For others, like the P0124 code, other signs may be evident. Listed below are some of the common symptoms of the P0124 trouble code:
- Malfunction indicator lamp (MIL) or check engine light is on
- No unusual symptoms may be noticed in many cases
- In some cases, engine hesitation during acceleration
- In some cases, the engine is hard starting or may not start at all
- Increased emissions
- Poor fuel efficiency
- Other emissions-related codes may also be stored
- Vehicle stuck in “limp” mode
How to Diagnose the P0124 Code
Determining the root cause of trouble codes is both challenging and time-consuming because there are multiple possible causes for each code. In addition, the diagnostic process should be thoroughly done, as misdiagnosis could lead to even more problems and more expensive repairs down the line.
As for the P0124 trouble code, a couple of misdiagnoses may be given. For example, the throttle position sensor may be replaced even when the problem is actually a dirty throttle body or poor throttle position sensor wiring. The pedal position sensor may also be replaced even when the actual problem is torn or damaged floor mats.
To avoid misdiagnosis, it’s important to have a reliable source of repair information. In this regard, repair manuals and databases are your best options because not only do they provide detailed instructions, they contain helpful illustrations and diagrams as well.
However, if you don’t have access to repair manuals or databases, there are other materials available online. Blogs, how-to videos, and even digital magazines provide additional information about trouble code repair as well.
How to Fix the P0124 Code
A thorough diagnosis is vital in achieving a long-term solution for trouble codes. However, there is another important factor to be considered as you try to repair diagnostic trouble codes, such as P0124.
The fact that vehicles differ, depending on the manufacturer, should be taken into account when planning repairs. Terminology, components, and repair instructions vary according to the vehicle’s make. If you’re trying to troubleshoot a P0124 on a Ford vehicle, the same diagnostic procedures may not be applicable to a P0124 on a Toyota vehicle.
While having accurate repair sources helps you understand the issue at hand, consulting a certified professional is also beneficial, especially if you’re unfamiliar with trouble code repairs. Also, if you’re not confident with your own troubleshooting skills, you can have a mechanic or technician do the job for you.