P0841 Code: Transmission Fluid Pressure Sensor / Switch “A” Circuit Range Performance

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on August 19th, 2024

Reading Time: 5 minutes
Summary
  • The diagnostic trouble code (DTC) P0841 indicates “Transmission Fluid Pressure Sensor / Switch ‘A’ Circuit Range Performance.”
  • Your vehicle’s powertrain control module (PCM) will trigger this code when the “A” input sent by the transmission fluid pressure sensor (TFPS) isn’t within the range stored in the PCM or transmission control module (TCM).
  • The P0841 code can also get set if the voltage drops because of corroded switch contacts or if the hydraulic system develops a pressure leak.
  • Some of the most common causes of the P0841 code are various problems with the signal circuit, a faulty TFPS sensor, and a defective PCM.
  • Some of the symptoms of a P0841 code include an illuminated check engine or transmission light, a change in shift quality, higher fuel consumption, and the vehicle going into limp mode.

If your scan tool displays a P0841 code after having noticed a possible transmission concern, this article will explain what this diagnostic trouble code (DTC) means and how to troubleshoot it.

What Does the P0841 Code Mean?

Diagnostic trouble code (DTC) P0841 stands for “Transmission Fluid Pressure Sensor / Switch ‘A’ Circuit Range Performance.” It’s a generic powertrain code that applies to most modern vehicles that have OBD-II diagnostics.

The transmission fluid pressure sensor (TFPS) is responsible for converting transmission pressure into electrical signals for the powertrain control module (PCM) or transmission control module (TCM). This voltage signal is used by the PCM or TCM to determine the transmission’s operating pressure. If the “A” input is not within the range stored in the PCM or TCM, a P0841 code might register. Though this DTC is primarily an electrical circuit issue, mechanical issues, such as internal leaks, cracked balls in the valve body, low operating pressure, and a stuck valve, can also cause it to set.

If the “A” input coming from the TFPS is not within the range stored in the PCM or TCM, a P0841 code can register.

More About the Pressure Switch and Shift Solenoids

The operative word in the description of code P0841 is “performance.” This pressure switch and the others are expected to respond when certain conditions are met in regard to shift solenoids and valve body action. It’s basically a feedback loop. If a shift solenoid command is issued by the PCM and the pressure switch doesn’t indicate the expected pressure change (either intermittently or every time), a performance code for the switch will be set.

If the switch contacts are dropping voltage (corroded), code P0841 can also be set or if there is a pressure leak in the hydraulic system.

This simplified schematic doesn’t have a pressure switch “A” but illustrates the electrical layout of a transmission with shift solenoids and pressure switches. | Source: Richard McCuistian

Note: The definition of code P0841 may be different depending on the vehicle manufacturer, type of TFPS. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0841 Code?

A P0841 code doesn’t necessarily indicate a problem with a specific transmission fluid sensor. Other factors may cause the PCM to store this code. For an accurate diagnosis, make sure to check all the parts in your circuit. The following are possible causes of the P0841 code:

  • Open in the signal circuit
  • A voltage short in the signal circuit to the TFPS sensor
  • A voltage ground in the signal circuit to the TFPS sensor
  • Faulty TFPS sensor
  • Defective PCM
An increase in fuel consumption is also one of the common symptoms of the P0841 code.

What are the Common Symptoms of the P0841 Code?

A P0841 code might be accompanied by other diagnostic trouble codes, so you might observe some symptoms listed here. However, if your PCM only stores a P0841 code, your vehicle might exhibit the following symptoms:

  • Illuminated check engine or transmission light
  • Change in shift quality
  • Higher fuel consumption
  • Vehicle may go into limp mode (Applies to vehicles that have limp mode)

How to Diagnose the P0841 Code

The P0841 code might share symptoms, causes, and affected areas with other DTCs. You must follow the prescribed diagnostic procedures for your specific vehicle to determine the underlying problems of your P0841 code. The following video shows a general diagnostic procedure for the P0841. We recommend doing your own research before attempting any repairs on your vehicle.

How to Fix the P0841 Code

There’s a lot to consider when troubleshooting a P0841 code. Remember to follow the prescribed diagnostic and repair procedures for your specific vehicle. You can find all the information you need in your vehicle’s repair manual. Some manufacturers have released technical service bulletins that may help you diagnose your DTCs. An ALLDATA subscription is an excellent source for automotive repair information.

Keep in mind that some repair procedures might not be applicable for your vehicle’s make and model. What might work to resolve a P0841 code in a Dodge might not work for a Ford. If you have the budget, you can get your vehicle serviced by a certified mechanic to avoid the hassle of having to do everything yourself.

Other Notes About P0841

The transmission system contains numerous components that can fail over time. Here are related TFPS “A” circuit codes.

  • P0840 Code: Transmission Fluid Pressure Sensor/Switch “A” Circuit
  • P0842 Code: Transmission Fluid Pressure Sensor/Switch “A” Circuit Low
  • P0843 Code: Transmission Fluid Pressure Sensor/Switch “A” Circuit High
  • P0844 Code: Transmission Fluid Pressure Sensor/Switch “A” Circuit Intermittent

How To Get a Quality Replacement TFPS for Your Vehicle

Unfortunately, you can’t just wait out the issue triggering a P0841 code because it isn’t a problem that’s just going to go away on its own. If ignored for too long, it’ll most likely make things much worse for your vehicle and lead to some costly repairs down the line. Thankfully, getting a new TFPS is easy with CarParts.com.

Thanks to our convenient search filters, you can order a new TFPS in just a few clicks. You’ll also find that each product comes with an accurate and detailed fitment guide, so you don’t have to worry about buying the wrong product. If you need any help, please don’t hesitate to reach out to us, as our customer service hotlines are always open.

Order a new TFPS at CarParts.com today, and you’ll be back on the road before you know it!

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Written By CarParts.com Research Team

Automotive and Tech Writers

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Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician