In the world of automotive diagnostics, DTC codes play a crucial role in identifying and troubleshooting various issues with vehicles. One such code is the P0790 DTC code, which is related to a problem in the transmission system. In this article, we will delve deep into the P0790 DTC code, its significance, causes, and possible solutions, providing you with a comprehensive understanding of this specific diagnostic trouble code.
The P0790 DTC code refers to a problem with the Normal/Performance switch circuit within the transmission shift solenoid “E.” This code is specific to vehicles equipped with an automatic transmission and is commonly encountered in certain makes and models. When this code is triggered, it signifies that there is an electrical issue in the switch circuit, which might affect the performance and overall operation of the transmission system.
When the P0790 DTC code is present, it may manifest through various symptoms. It’s important to recognize these symptoms as they can provide valuable insights into the underlying issue. Common symptoms associated with the P0790 DTC code include:
Harsh Shifting: One common symptom of the P0790 DTC code is the transmission’s tendency to shift gears in a harsh or rough manner. This can be felt as a sudden jerk or lurch while the vehicle is in motion.
Transmission Slippage: Another symptom is intermittent or persistent transmission slippage. This occurs when the transmission fails to engage the targeted gear properly, leading to a loss of power and compromised acceleration.
Transmission Failure to Shift: The P0790 DTC code can also cause the transmission to fail to shift into the desired gear when commanded. This can result in prolonged or delayed shifting, affecting the vehicle’s overall performance.
Understanding the possible causes behind the P0790 DTC code is crucial in order to perform an accurate diagnosis and resolve the issue effectively. Here we will discuss some common causes of this code:
One possible cause of the P0790 DTC code is a faulty or malfunctioning Normal/Performance switch. This switch, located within the transmission shift solenoid “E,” is responsible for selecting the appropriate gear mode as per the driver’s input. If the switch fails to function properly, it can trigger the P0790 code.
In some cases, the P0790 DTC code may be caused by a faulty wiring harness or connectors within the transmission system. Over time, these components can become damaged, corroded, or disconnected, resulting in a poor electrical connection and triggering the code.
The vehicle’s TCM, which is responsible for controlling the transmission’s operation, might experience a malfunction or failure, leading to the P0790 DTC code. This can occur due to various reasons, such as electrical issues, component failures, or software glitches.
Diagnosing and fixing the P0790 DTC code requires a systematic approach and the use of proper diagnostic tools. While it is recommended to consult a professional mechanic, here are a few general steps that can be taken:
Scan the Vehicle: Connect an OBD-II scanner to the vehicle’s OBD port and retrieve the trouble codes. Ensure P0790 is the only code present, as other codes might provide additional insights.
Inspect Wiring and Connectors: Thoroughly examine the wires and connectors associated with the Normal/Performance switch and the transmission system. Look for any signs of damage, corrosion, or loose connections. Repair or replace any faulty components as necessary.
Test the Normal/Performance Switch: Use a multimeter or specialized transmission diagnostic tool to test the Normal/Performance switch for continuity and proper functionality. Replace the switch if it is found to be defective.
Check the TCM: If the switch and wiring appear to be functioning correctly, the TCM might be the culprit. Consult the vehicle’s service manual to locate the TCM and test it for any faults. If necessary, consider replacing the TCM with a new or appropriately programmed unit.
Clear the Trouble Code: After the repair process is complete, use the OBD-II scanner to clear the trouble codes. Take the vehicle for a test drive to ensure that the P0790 DTC code does not reappear.
Q1: Can I drive with the P0790 DTC code?
A: It is generally advisable to avoid driving with the P0790 DTC code present. The code indicates a potential issue with the transmission system that can affect its performance and drivability. Continuing to drive the vehicle without addressing the underlying problem may cause further damage and increase the risk of a breakdown.
Q2: How much does it cost to fix the P0790 DTC code?
A: The cost of fixing the P0790 DTC code can vary depending on several factors, including the make and model of the vehicle, labor charges, and the specific component that needs to be repaired or replaced. It is best to consult a professional mechanic for an accurate estimate based on your vehicle’s requirements.
Q3: Can I fix the P0790 DTC code myself?
A: While some DIY enthusiasts may have the necessary skills and tools to diagnose and fix the P0790 DTC code, it is generally recommended to seek professional assistance. Transmission systems can be complex, and inaccurate diagnosis or improper repairs can lead to further damage and costly repairs. A qualified mechanic will have the expertise to provide an accurate diagnosis and perform the necessary repairs.
The P0790 DTC code is a specific diagnostic trouble code related to the Normal/Performance switch circuit of the transmission. This code signifies an electrical issue that can lead to symptoms such as harsh shifting, transmission slippage, and failure to shift. Identifying the possible causes and taking the necessary steps to diagnose and fix the code is crucial in order to maintain the overall performance and efficiency of the vehicle’s transmission system. Remember to consult a professional mechanic for accurate diagnosis and repair of the P0790 DTC code.
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.
