Which Codes Will This Page Cover?
● P0122 Throttle/Pedal Position Sensor/Switch “A” Circuit Low
● P0120 Throttle/Pedal Position Sensor/Switch “A” Circuit
● P0121 Throttle/Pedal Position Sensor/Switch “A” Circuit
● P0123 Throttle/Pedal Position Sensor/Switch “A” Circuit High
● P0124 Throttle/Pedal Position Sensor/Switch “A” Circuit Intermittent
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What Is the P0122 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
A P0122 code is the generic OBD-II code defined as “Throttle Pedal Position Sensor/Switch (TPS) A Circuit Low Input.” This code relates to the vehicle’s Engine Control Module (ECM) and TPS Sensor Circuit A output voltage and is triggered when the voltage falls below the sensor’s anticipated range. Most vehicles use a 5 volt reference signal in this system, with the TPS varying the voltage in response to where the throttle pedal is or how far down you press on the gas pedal. This is a linear relationship to pedal input and goes up to about 4.6 volts. With that said, the P0122 code triggers when your vehicle’s ECM detects that it has fallen below that amount.
Every sensor or system in a vehicle has a designated voltage range. The structures that make up these sensors and systems need a certain amount of voltage to perform their specific tasks as intended. Therefore, if the voltage exceeds or drops below a certain predefined threshold, these sensors and systems will stop working correctly or entirely malfunction. Thus, the ECM, TPS, and similar sensors and systems need to monitor voltages closely.
What Are the Symptoms of a P0122 Code?
If your vehicle encounters a P0122 code issue, several symptoms may occur individually or all at once. Additionally, your car may not experience any severe symptoms whatsoever for quite some time. However, one of the first things you may notice if you encounter a symptom is that the ECM will turn the Check Engine Light on your vehicle’s dashboard. Once the Check Engine Light is on, the car will enter a failsafe mode that cuts the current to the throttle actuator, which places the throttle valve to six degrees or less opening. One thing you should immediately note is that the failsafe mode and the symptoms it triggers may vary depending on the make and model of your car, as each manufacturer has its own failsafe ECM strategy.
One of the many functions of an ECM is to control the vehicle’s engine speeds by controlling its fuel injection and timing. If your car encounters the P0122 code, it may experience a significant decrease in performance and speed, and you may have difficulties driving and accelerating as throttle response may become limited. Also, when turned on and stationary, your vehicle may idle much higher than usual.
What Are Some Causes of a P0122 Code?
One of the most common causes of the P0122 code is a faulty or broken TPS. Another common cause is when the TPS is mounted incorrectly. If the TPS isn’t mounted or functioning correctly, this will cause an incorrect or faulty reading of output voltage levels to your vehicle’s ECM. Some other possible causes of the code are faulty or frayed TPS wiring or a TPS circuit short to ground. Sometimes the problem isn’t with the TPS in particular but with your vehicle’s pedal position switch or sensor. As with the TPS, if the pedal position switch or sensor is faulty or the wiring is frayed or damaged, it may cause the code to be triggered. Your vehicle’s pedal position switch or sensor can sometimes get blocked by debris on the floor mat, so it’s important to vacuum and clean your car as regularly as possible.
How Serious Is the P0122 Code?
Depending on your vehicle’s specific make and model, the severity of the P0122 code issue can vary. A car may not encounter any serious problem for quite some time other than a Check Engine light illuminating on the dashboard until the issue worsens.
On the other hand, depending on your vehicle’s ECM fail safe strategy, your vehicle may immediately go into failsafe mode. When this occurs, your vehicle’s performance may be significantly affected, and it may encounter significant issues with acceleration, high idle, limited speeds, and even stalling. We highly recommend addressing this issue as soon as possible and getting your vehicle checked out by a qualified technician before further damage occurs.
Can I Still Drive with a P0122 Code?
Depending on the severity of the issue and the make and model of your vehicle, you may be able to operate it but with varying degrees of performance and driving-related issues. In most cases, you will be able to operate a vehicle if a P0122 code is shown, but professionals strongly discourage it for extended periods. If your vehicle is experiencing excessive idling or difficulty accelerating problems, you shouldn’t wait any longer and should drive to get it inspected as soon as possible.
How Easy Is It to Diagnose a P0122 Code?
Diagnosing a P0122 issue consists of performing several steps to troubleshoot and diagnose the issue successfully. A qualified technician will first scan the vehicle’s ECM and TPS, document the P0122 code and any other code that may show up, and then analyze the freeze frame data to spot when the P0122 code or other codes were set. The technician will then clear the vehicle’s OBD-II fault codes and retest the car to see if the P0122 code or other codes return. The technician may then scan and test the TPS to compare the TPS circuit A and B data and, if necessary, perform the TPS pinpoint tests per the manufacturer’s recommendations. After analyzing the results, if the TPS requires a replacement, the technician will then replace the vehicle’s TPS, clear all of the codes, and perform a road test.
For a more detailed list of service centers near you, visit KBB’s service center list.
How Difficult Is It to Inspect a P0122 Code?
Before replacing the TPS after the scan and analyzing the data, the technician will proceed with a thorough inspection of the TPS to see if it’s properly mounted, exhibits any visible damage, or if there are any connection or wiring issues such as damaged connections or wires. Before replacing the TPS, qualified technicians will always physically inspect the TPS to see if the problem may be fixed by attending to any bad connections or replacing any damaged wiring.
Correctly diagnosing the P0122 issue can be difficult depending on its severity and is precisely why most people leave it to qualified technicians. We don’t recommend self-diagnosing the P0122 code issue because of the sheer complexity of the entire process.
Need Additional Help with Your P0122 Code?
A P0122 code issue can cause no immediate symptoms until other more indirect symptoms are noticed or your vehicle experiences significant performance or goes into failsafe mode. Therefore, if you’re experiencing any idling or acceleration issues while driving your vehicle, you shouldn’t wait any longer to get it inspected by a proper technician to reduce the risk of further damage to your car.
For more information on the P0122 and other similar diagnostic codes, visit KBB’s vast library of OBD-II codes.
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