P0875 OBD-II Trouble Code: Transmission Fluid Pressure Sensor/Switch D Circuit

P0875 code definition

The P0875 code indicates that the transmission fluid pressure is not correct, according to the manufacturer’s specifications.

What the P0875 code means

The fluid pressure sensor provides the PCM with the data necessary to monitor the transmission performance. If the fluid pressure increases, the voltage reading from the pressure sensor will increase; if the pressure decreases, the voltage decreases. If the PCM finds that the voltage is either decreased or increased in a situation where it should be the opposite, the P0875 code is stored.

What causes the P0875 code?

The most common cause of the P0875 code is dirty, contaminated, or low transmission fluid, often related to a lead. Other causes can include:

• A defective transmission high pressure pump
• Faulty temperature sensor
• Overheated engine
• Mechanic internal transmission failures.
• A faulty PCM, in rare cases.

What are the symptoms of the P0875 code?

Some vehicle owners may notice no symptoms at all, and only observe the Check Engine lamp illuminating. However, the symptoms of the P0875 code can include:

• Overheated transmission fluid, which produces a distinctive smell
• Smoke from the transmission area
• Lack of engagement or disengagement from the transmission
• Harsh shifting or a slipping transmission.

How does a mechanic diagnose the P0875 code?

After verifying the code with an OBD-II scanner, all transmission-related faults should begin with a check of the transmission fluid. If the fluid is too low, it should be refilled; if the fluid is dirty, filled with debris, or smells burnt, it may be that the entire system must be flushed, and then refilled with clean transmission fluid.

After this, or any other repair, is performed, it’s important to clear the code from the PCM, and retest the system. This process helps the mechanic narrow down the exact cause of the issue. If the transmission fluid fix did not cause the code to disappear from the PCM, then next step is to inspect the electrical components, and to continue working through possible repairs until the correct issue is found.

Common mistakes when diagnosing the P0875 code

The two most common misdiagnoses with the P0875 code are:

• Not realizing that a transmission fluid has damaged vital transmission components, which will require the entire transmission to be rebuilt.
• Or, immediately assuming the transmission needs rebuilding without checking other possible causes first.

How serious is the P0875 code?

While some vehicle owners may not observe any symptoms, this code still indicates a serious issue that should be addressed right away. As time goes on, vehicle performance will decline until the vehicle is not drivable, and ignoring this trouble code could lead to greater issues down the road.

What repairs can fix the P0875 code?

Repairs to fix the P0875 code include:

• Refilling the transmission fluid, or flushing the system and refilling
• Replacing a defective transmission high pressure pump
• Replacing a faulty temperature sensor
• Repairing mechanic internal transmission failures
• Replacing a faulty PCM, in rare cases

Need help with a P0875 code?

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