P0990 DTC Code


In the automotive world, DTC codes play a crucial role in diagnosing and identifying problems within a vehicle’s system. One such DTC code is P0990, which specifically relates to issues with the transmission fluid pressure sensor. To understand the intricacies of this code and its implications, let’s dive deep into the details and explore the significance of P0990 in the context of automotive diagnostics.

Understanding P0990 DTC Code

The P0990 DTC code is a generic powertrain code that indicates a potential problem with the transmission fluid pressure sensor E. Specifically, it refers to a malfunction or improper performance of this sensor. To fully comprehend the significance of this code, we’ll delve into the role of the transmission fluid pressure sensor, its function, and how it relates to overall vehicle performance.

Transmission Fluid Pressure Sensor Function

The transmission fluid pressure sensor, sometimes referred to as the pressure control solenoid, measures the hydraulic pressure within the transmission. This sensor provides crucial data that helps the powertrain control module (PCM) manage various aspects of the transmission system, such as shifting points, torque converter lockup, and overall transmission performance.

By monitoring the pressure, the transmission fluid pressure sensor assists the PCM in making accurate adjustments to optimize gear shifting and prevent potential damage to the transmission system. When the sensor malfunctions or fails to provide the necessary data, the PCM may trigger the P0990 DTC code, indicating an issue that requires attention.

Symptoms of P0990 DTC Code

Identifying the symptoms associated with the P0990 DTC code is essential for prompt diagnosis and resolution. Here are some common signs that may indicate the presence of this code:

  1. Warning Light Illumination: The most immediate indication of the P0990 DTC code is the illumination of the check engine light on the vehicle’s dashboard. This serves as a general warning that something within the transmission system requires attention.

  2. Transmission Performance Issues: A malfunctioning transmission fluid pressure sensor may lead to noticeable problems with the vehicle’s transmission performance. These issues can include delayed or harsh shifting, slipping gears, or even failure to engage certain gears.

  3. Decreased Fuel Efficiency: As the transmission system struggles to operate optimally with a malfunctioning sensor, it may result in decreased fuel efficiency. This occurs due to the compromised ability to adjust gear shifting points and torque converter lockup, leading to inefficient power delivery and increased energy waste.

Identifying these symptoms early on can help avoid further damage to the transmission system and improve overall vehicle performance.

Diagnosis of P0990 DTC Code

When presented with the P0990 DTC code, a proper diagnosis is crucial to identify the underlying cause and take appropriate corrective measures. Automotive technicians usually follow a specific set of steps to diagnose this code:

1. Code Reading

Using an OBD-II scanner, the technician retrieves the stored codes from the vehicle’s PCM. The P0990 code will be among the codes displayed, indicating the issue with the transmission fluid pressure sensor.

2. Visual Inspection

A visual inspection of the transmission system is necessary to detect any visible damages, loose connections, or signs of wear and tear. This includes examining the wiring connected to the transmission fluid pressure sensor and visually inspecting the sensor itself.

3. Sensor Testing

To determine the functionality of the transmission fluid pressure sensor, a series of tests are performed. This may involve utilizing specialized diagnostic equipment capable of monitoring the sensor’s output and comparing it to the manufacturer’s specified values. If the sensor fails this test, it indicates a need for replacement.

4. Wiring and Connector Check

As the wiring and connectors play a crucial role in delivering accurate readings from the transmission fluid pressure sensor, they should be thoroughly inspected. Wiring defects, corrosion, or loose connections can also contribute to the P0990 DTC code and must be rectified.

5. Confirmation Test

After addressing any identified issues, an additional test or road test may be conducted to ensure that the P0990 code has been resolved. This confirms that the corrective measures taken have effectively rectified the problem.

Frequently Asked Questions (FAQs)

  1. Q: Can I continue driving with the P0990 DTC code present?

    A: While the vehicle may still be drivable with the P0990 DTC code, it is advisable to have the issue addressed promptly. Continuously driving with a malfunctioning transmission fluid pressure sensor can lead to further damage to the transmission system and potentially more expensive repairs.

  2. Q: What causes the P0990 DTC code?

    A: The P0990 DTC code can be triggered by various factors, such as a faulty transmission fluid pressure sensor, damaged or loose wiring connections, or problems with the powertrain control module. A thorough diagnostic process is necessary to determine the specific cause in each case.

  3. Q: Can I fix the P0990 DTC code myself?

    A: While some automotive enthusiasts may have the skills to attempt repairs themselves, resolving the P0990 DTC code typically requires professional expertise. It is recommended to consult a qualified automotive technician who has the necessary tools and experience to diagnose and rectify the issue accurately.

In conclusion, the P0990 DTC code relates to a malfunctioning transmission fluid pressure sensor, impacting the overall performance of the vehicle’s transmission system. Identifying the symptoms, performing a thorough diagnosis, and taking appropriate corrective measures are crucial for resolving this issue efficiently. Consulting a qualified automotive technician will ensure the problem is dealt with effectively to restore optimal vehicle functionality.

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.


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