If you encounter a P0846 code upon connecting a scan tool to your vehicle, this article can help you learn more about its meaning, symptoms, and causes.
Diagnostic trouble code (DTC) P0846 code is defined as “transmission fluid pressure sensor/switch ‘B’ circuit range performance.” It’s a generic, transmission-related trouble code that typically applies to automatic transmission vehicles.
Automatic transmissions have several solenoid groups that direct transmission fluid to various hydraulic circuits. The solenoids are grouped into circuits and are labeled A, B, C, and so on. The transfer of these fluids is what allows the transmission to change gears.
The transmission fluid pressure sensor/switch (TFPS) reads the pressure in the transmission, converts it into an electrical signal, and sends it to the powertrain control module (PCM) or transmission control module (TCM). The PCM or TCM uses this voltage signal to determine transmission operating pressure.
The P0846 code is triggered when the PCM or TCM detects that the voltage coming from the TFPS doesn’t match normal operating voltages stored in its memory. The P0846 code is typically a TFPS sensor circuit issue. However, it can also be caused by various mechanical issues like leaks or low fluid pressure.
For more technical information that can help you better grasp how codes like P0846 are set, read our note about the pressure switch and shift solenoids.
Note: The definition of the P0846 code may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.
As previously mentioned, the P0846 code is usually triggered by TFPS issues. However, it can also be triggered by other issues such as:
Since this is most likely an electrical failure, the PCM or TCM can compensate for the issue to some degree. The PCM or TCM might modify transmission shifting settings if it’s electronically controlled. That said, the P0856 code can still cause symptoms such as the following:
After you’ve plugged in a scan tool and identified the P0846 code, identifying which part is faulty can be difficult. The transmission is usually difficult to access and requires a lot of time and labor to be able to disassemble them for inspection. To get a proper diagnosis, you may want to consult a professional.
If you want to learn more about the diagnostic process, you can check out the video below:
Prior to any repair, you first need to have an accurate diagnosis of the issue. There isn’t a cure-all fix for any OBD-II code. The process of fixing it is dependent on what part is causing the issue. Since there are a variety of possible causes for the P0846 code, there are also several possible ways to fix it.
After accurately identifying the cause of the issue, you can consult online auto repair resources and how-to guides.
Since all vehicles have different designs and configurations, a fix for an OBD-II code on a Jeep may not be applicable to a Mazda. You should consult your vehicle’s repair manual when it comes to troubleshooting and repairing diagnostic trouble codes. Chilton repair manuals may also be useful. However, ALLDATA subscriptions are even better, as they provide detailed factory repair information for drivers who want to do repairs themselves.
There are several other codes that are related to the TFPS sensor. These include the P0845, P0847, P0848, and P0849 codes. This code typically applies to all vehicles equipped with OBD-II systems including but not limited to Jeep, Nissan, and Honda vehicles.
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.