P0847 Code: Transmission Fluid Pressure Sensor / Switch “B” Circuit Low

On-board diagnostic (OBD) codes help mechanics and vehicle owners identify possible issues in a vehicle. But before you can troubleshoot and resolve these problems, it’s important to know what these codes mean.

Code P0847 is one of many trouble codes that can be logged and retrieved from the OBD system. Here is some helpful information that can help you understand what getting this code may mean for your vehicle.

What Does the P0847 Code Mean?

Diagnostic trouble code (DTC) P0847 stands for “Transmission Fluid Pressure Sensor/Switch ‘B’ Circuit Low.” This code is logged when the powertrain control module (PCM) detects an issue with the hydraulic clutch or the pressure switch.

Basically, the pressure switches in a transmission are for feedback and shift timing.

Honda describes the P0847 this way:

1. This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

2. If DTC P0847 is stored in the PCM, the transmission does not shift to any gear other than 3rd or 6th gear because of the fail-safe function.

The transmission fluid pressure sensor/switch converts pressure from the mechanical transmission into an electrical signal for the PCM. The PCM then uses this information to determine transmission operating pressure.

The P0847 code is set if the “B” input does not match normal operating voltages stored in the PCM’s memory. The code can also be logged due to a variety of different reasons, ranging from a faulty sensor to internal mechanical issues inside the transmission.

Depending on the severity of the problem, related error codes might also be stored with this DTC. Code P0847 is very similar to error codes P0845, P0846, P0848, and P0849.

Note: The definition of code P0847 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0847 Code?

• Transmission fluid pressure sensor failure
• Issues with the powertrain control module (PCM) or transmission control module (TCM)
• Wiring problems
• Low transmission fluid level
• An internal transmission mechanical problem

What are the Common Symptoms of the P0847 Code?

• Illuminated check engine light
• Change in shift quality
• Poor fuel efficiency
• Transmission may not shift properly
• Vehicle in limp mode

How to Diagnose the P0847 Code

Different makes and models can set the error code P0847. But this does not mean that there is a one-size-fits-all approach to diagnosing its underlying cause. The steps for troubleshooting this code will vary depending on your specific vehicle.

Check out the video below to get an idea of what the diagnostic process for this code might involve:

How to Fix the P0847 Code

Code P0847 shares similar triggers and symptoms with other engine codes. However, the appropriate diagnostic and repair procedure will depend on the specifications of your vehicle. If you’re unfamiliar with auto repair, it’s best to leave the job to a mechanic.

If you’re considering troubleshooting this code on your own, it’s a good idea to refresh your automotive knowledge before attempting any fixes. Always consult a vehicle-specific repair manual or an online repair database to learn the appropriate diagnostic procedures for this code.