How to Fix P0122 Code on Dodge Cummins (Expert Insights)

Engine air intake and regulation is a crucial aspect and is monitored by the TPS. Any issue involving it may have negative impacts on acceleration and fuel economy. That said, error codes are detected when the problems are identified on the TPS.

The error code P0122 is “Throttle Pedal Position Sensor/Switch (TPS) A Circuit Low Input”. It means that the ECM has detected a lower output voltage from the TPS Circuit A compared to the expected voltage.

There are many reasons behind this error code, and it has several symptoms. This article will discuss all of those and show you some reasonable fixes.

Therefore, let’s dive into the write-up.

How to Fix P0122 Code on Dodge Cummins

What Does Code P0122 Mean On Dodge Cummins?

The error code P0122 is associated with a lower output voltage from the TPS circuit. It is mainly detected by the PCM when the Throttle Position Sensor (TPS) exhibits a much lower voltage than usual.

The main job of the Throttle Position Sensor is to guide the system in monitoring the air-to-fuel ratio. And when it is about triggering this error code, the root of the problem can also be from the electronic throttle pedal.

The breakdown of the code below will give you a better idea:

  • P = Powertrain
  • 0 = Generic Number that is derived from the SAE standard
  • 1 = Fuel and Air Metering
  • 22 = Specific Fault Index ( In this case, the problem denotes the lower voltage output detection by TPS than usual)

How Serious Is Code P0122 On Dodge Cummins?

The error code P0122 on your Dodge Cummins engine won’t have severe implications immediately. It is one of the least harmful codes and will give you breathing space. You can easily take a week or two and then start the process of code removal. 

However, prolonging the code removal will result in different outcomes gradually. There will be an increase in the engine pollutants on the surrounding components. Also, fuel consumption will see an increase. 

Since the issue is associated with the throttle, the throttle response will also reduce to a great extent. On the other hand, the ECM can adopt the failsafe mode. As a result, there would be a lack of acceleration and limited speeds when driving. 

What Causes Code P0122 On Dodge Cummins?

Several reasons for the P0122 code. In addition, some of these reasons are common for all types of error codes, while some are only for this particular issue. 

That said, the most prominent causes of the P0122 error code are given below:

  • Malfunctioning Throttle Position Sensor/Switch 
  • Corroded wiring and connections 
  • Debris accumulation on Pedal Position Sensor
  • Faulty mounting of TPS
  • Defective Pedal Position Sensor 
  • Damaged PCM 

How To Fix Code P0122 On Dodge Cummins?

Error code P0122 may be detected due to several reasons. There isn’t any single fix that might resolve this issue altogether. For this reason, we have added a step-by-step fix to help you address this error code.

Here are the steps that will help you resolve P0122 on the Dodge Cummins engine:

Step-1: Locate A Circuit

The first step would be to locate the “A” Circuit on the engine. It is where all the issues take place. To find this circuit, the best possible way would be to consult the vehicle repair manual. 

You will find all the directives that will guide you to the exact position of the circuit.

Step- 2: Visually Inspect Sensor

After you locate the position of the circuit, you’ll have a good view of the Throttle Position Sensor. You need to inspect the sensor rigorously and check whether there is any damage.

The loose or defective connections in the sensor sometimes result in the detection of error codes. Also, check the presence of any damaged or corroded wire. Because these corroded wires are sometimes the prime reason for code detection.

Step-3: Check Voltage

A simple voltage checkup is required if the connections and surrounding wires are alright. For this, you would need a multimeter and carry out a few tasks.

You need to Coincide the negative wire tab of TPS with the negative probe and the positive tab with the positive probe of a multimeter. If the multimeter shows the reading of 5 volts, the TPS is working correctly. Or else it either needs adjustment or replacement.

Step-4: Adjust TPS Placement

Faulty placement of the TPS might result in the error code P0122. Therefore, adjustments need to be made to help eradicate the code. To carry out this process, follow the steps mentioned below:

  • Untighten the mounting bolts with a screwdriver, which will help you to rotate the sensor
  • Initiate back probing with TPS for monitoring voltage signal
  • Turn on the ignition key
  • Place throttle plate as per the service manual
  • Check if the voltage readings are similar to the reference voltage
  • Rotate and check the readings again
  • Tighten up the screws

Step-5: Replace TPS

If none of those mentioned above methods solves the problem, it is better to replace TPS. The best option would be to have a mechanic consultation, which would ensure an efficient solution altogether.

Other Symptoms Of Getting P0122 Code On Dodge Cummins

Typical symptoms like variable speeds or increased fuel consumption aren’t the only symptoms. Several other symptoms can exhibit are:

  • Reluctance on acceleration
  • Frequent engine idling
  • ECM getting control over fuel injection and timing
  • Check engine light constantly on

How Much Does It Cost To Fix Code P0122 On Dodge Cummins?

The cost of fixing the P0122 code is the mechanic and the parts costs. Since one of the main fixes is the replacement of the TPS itself, it would incur you $80-105 for parts, and the labor cost would be another $40-90. 

Other than this, if corroded wires are there, new wires would cost less than $5. While there may be some other costs, these are the necessary costs you must have to secure.

Can You Drive Your Dodge Cummins With Code P0122?

Yes, driving the vehicle with the P0122 code is not an issue. This code isn’t severe and won’t cause massive problems for at least a week or two.

However, prolonging the fix might result in drawbacks. There would be engine idling, fume emission, debris settling on components, etc. If you don’t want to face such additional consequences, it would be better if you take steps to fix the code within a week or two.


The low output voltage in TPS might not seem something serious at the beginning. But not fixing this might result in various other issues. That said, the primary focus would be to try fixing the code using appropriate steps before it gets too late.

Engine frequently idling or variable acceleration isn’t a good thing. So, if the fix for the Dodge Cummins engine is to replace TPS, consult a mechanic then.

Moreover, driving a vehicle with such codes won’t be an issue when detected. But in the long run, it can harm the engine performance.

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