P0878 DTC Code: Explained and Resolved


In the world of automotive diagnostics, DTC codes play a crucial role in identifying potential issues within a vehicle. One commonly encountered diagnostic trouble code is P0878. In this article, we will dive deep into understanding what the P0878 DTC code means, its potential causes, and possible solutions to resolve it. So, let’s get started!

Understanding the P0878 DTC Code

The P0878 DTC code specifically refers to a transmission fluid pressure sensor/switch “C” circuit high. It indicates that there is an excessive voltage or high circuit resistance in the transmission fluid pressure sensor circuit, causing the pressure reading to be higher than expected.

Possible Causes of the P0878 DTC Code

Several factors might contribute to the triggering of the P0878 DTC code. Let’s take a look at some of the potential causes:

  1. Faulty Transmission Fluid Pressure Sensor/Switch: A malfunctioning sensor or switch can send inaccurate signals, leading to high voltage readings and the subsequent activation of the P0878 DTC code.

  2. Wiring or Connector Issues: Damaged, loose, or corroded wiring connections between the sensor and the main control unit can disrupt the signal transmission, resulting in erroneous readings.

  3. Transmission Fluid Problems: Contaminated, low, or incorrect transmission fluid levels can affect the performance of the sensor, causing it to generate high voltage readings.

  4. Faulty Transmission Control Module (TCM): The TCM, responsible for receiving and interpreting sensor data, might be the source of the issue if it fails to accurately process the signals from the transmission fluid pressure sensor/switch.

Resolving the P0878 DTC Code

Now that we have a better understanding of the potential triggers of the P0878 DTC code, it’s time to explore possible solutions to resolve it. Here are some steps you can take:

  1. Sensor/Switch Inspection: Begin by inspecting the transmission fluid pressure sensor/switch. Look for any physical damage, oil contamination, or signs of corrosion. If you come across any issues, replacing the sensor/switch might be necessary.

  2. Wiring and Connector Check: Next, examine the wiring harness and connectors associated with the transmission fluid pressure sensor/switch. Ensure that the connections are secure, clean, and free from corrosion. Repair or replace any damaged components as needed.

  3. Transmission Fluid Analysis: Check the transmission fluid level and condition. If the fluid is low, contaminated, or the incorrect type, a fluid change is recommended. Ensure that you use the manufacturer-recommended fluid to prevent further issues with the sensor.

  4. TCM Assessment: If the above steps don’t resolve the P0878 DTC code, a thorough assessment of the Transmission Control Module is necessary. This task is best left to a qualified automotive technician with access to diagnostic equipment, as they can accurately diagnose and repair any faults with the module.

Frequently Asked Questions

  1. Q: Can I drive my car with the P0878 DTC code?

    A: It is generally not recommended to drive your vehicle with an active DTC code, including P0878. Ignoring the issue might lead to further transmission damage or potential safety hazards. It is best to address the problem promptly.

  2. Q: Can a P0878 DTC code be cleared without repairs?

    A: Clearing the DTC code without resolving the underlying issue is not recommended. Although clearing the code might temporarily turn off the check engine light, the problem will likely persist. It is crucial to identify and repair the root cause to prevent further troubles.

  3. Q: How much does it cost to fix the P0878 DTC code?

    A: The cost of fixing the P0878 DTC code varies depending on factors such as the specific vehicle, the needed repairs, and labor rates in your area. It is advisable to consult with a professional mechanic or a dealership for a more accurate estimate.

In conclusion, the P0878 DTC code indicates a transmission fluid pressure sensor/switch circuit high issue. By inspecting the sensor, checking the wiring, assessing the transmission fluid, and considering the Transmission Control Module, you can take steps towards resolving this error code. Remember, it is essential to address DTC codes promptly for the continued performance and safety of your vehicle.

About author


Meet Sam Mitchell, your experienced and reliable guide in the complex world of car fault codes. With a robust career spanning over 15 years as a professional car mechanic, John has the skills, knowledge, and practical experience to help you navigate car fault issues with confidence.


Leave a Reply