P0872 Code: Transmission Fluid Pressure Sensor / Switch “C” Circuit Low

The transmission fluid pressure (TFP) sensor measures the pressure exerted by the fluid flowing through the transmission. It sends its readings to the transmission control module (TCM), the computer that ensures that the transmission shifts gears smoothly and efficiently.

The TCM will log a P0872 code if it determines that the transmission fluid pressure sensor sent a signal with a lower voltage than expected.

What Does the P0872 Code Mean?

The diagnostic trouble code (DTC) P0872 indicates “Transmission Fluid Pressure Sensor/Switch “C” Circuit Low.”

Also referred to as the transmission fluid pressure switch, the TFP sensor is usually secured to the side of the valve body. It could also be attached to the side of the transmission case or body.

The TFP sensor converts the pressure in the transmission into a voltage signal. It sends its readings to the TCM or powertrain control module (PCM).

The TCM uses the readings to keep track of what pressure level the transmission is currently running at. It will warn the driver about critical transmission fluid pressure levels.

The PCM regularly checks the signals transmitted by the transmission fluid pressure sensor and compares them to the correct readings stored in its memory. If the voltage signal from sensor  “C” input is lower than it should be, the control module will set the generic code P0872.

Note: The definition of code P0872 can differ depending on the vehicle manufacturer. Check the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0872 Code?

• Transmission fluid pressure sensor stops working properly
• Wiring issue
• Faulty TCM
• Low fluid level
• Valve body issues
• Internal transmission failure

What are the Common Symptoms of the P0872 Code?

• Illuminated check engine light
• More fuel consumed and wasted
• Improperly shifting transmission

How to Diagnose the P0872 Code

The P0872 code is a generic powertrain/engine code that various makes and models can log. However, this does not mean that there is a one-size-fits-all solution to identify its underlying problem.

If you’re not confident about conducting diagnostic tests on your vehicle, it’s best to bring it to a professional mechanic. Otherwise, you can go ahead and diagnose the issue yourself. To help you get started, here is a video that can give you an idea of what the process might involve:

How to Fix the P0872 Code

Attempting to fix the P0872 code can become a challenging task if you don’t have the right tools and know-how to test the transmission fluid pressure sensor. There are many powertrain/engine codes that share the same symptoms as the P0872 code. So it’s usually best to leave the job to professionals. But if you have the right technical knowledge and hands-on experience, you can test and replace your transmission pressure sensor on your own. Make sure you refer to a vehicle-specific repair manual or an online repair database before you get started.