top of page
Tekniker

P0790 Fault-Error Code MODE SWITCH CIRCUIT FAILURE Sport, Eco, Snow

Updated: Aug 27

What is P0790 Fault-Error Code?

 

P0790 Fault-Error Code is a fault code in the OBD-II (On-Board Diagnostics II) system, which is a standard used in the automotive industry. This code is identified as "MODE SWITCH CIRCUIT FAILURE".



This fault code indicates a circuit failure of a mode switch used to determine the car's shifting mode. This mode switch is usually found on vehicles with automatic transmission and allows the driver to select the shift mode. For example, it allows switching to different driving modes such as "Sport", "Eco", "Snow".


MODE BUTTON CIRCUIT FAILURE can generally be caused by poor electrical connections, malfunction of the button itself, or any problem in the relevant circuit elements. This fault code may affect the car's shift mode selection or cause this function to not work completely.



What are the symptoms of P0790 Fault/Error Code?


Symptoms of the P0790 malfunction/error code may occur due to the vehicle's transmission or shift modes not working properly. These symptoms may include:


1. Inability to switch between gear shifting modes: There may be difficulty in switching to the vehicle's gear shifting modes or it may not be possible to switch at all.


2. Problems in gear shifting mode: It is possible to switch between gear shifting modes, but it may occur that the modes do not work correctly or do not show the desired performance.



3. Warning lights coming on: When the fault code is activated, a warning light may come on as a result of an error being detected by the vehicle's engine control unit (ECU). This can usually be warnings like "Check Engine" or "Transmission".


4. Abnormal gear changes: Abnormal or jerky gear changes may occur when switching between the vehicle's gear shifting modes.


5. High or low gear: The vehicle's automatic transmission may select a higher or lower gear than expected.



What could be the causes of P0790 Fault/Error Code?

 

There are several possible reasons why the P0790 fault/error code may occur. These may include:


1. Mode button malfunction: The mode button used to select the vehicle's gear shifting modes may be defective. The button itself may be broken or its connections may be broken.


2. Electrical connection problems: Connections in the vehicle's electrical circuits may be loose, corroded or cut. These connection issues can cause communication problems between the mode switch and the transmission control unit (TCM).


3. Damage to the mode button circuit: A component (e.g. resistor, capacitor) in the mode button circuit may be damaged, preventing the button from operating properly.


P0790

4. TCM malfunction: The transmission control unit (TCM) may be faulty. TCM receives the signals sent by the mode switch and sets the shifting mode accordingly. A malfunctioning TCM may simulate a problem in the mode switch circuit.


5. Software problems: Software errors or incompatibilities in the vehicle's control units can cause errors in the mode switch circuit.


6. Physical damage: There may be physical damage to the vehicle interior or circuits. For example, physical damage caused by water leakage or impact can affect electrical circuits and cause problems in the mode switch circuit.

 



What Steps Should Be Followed to Resolve the P0790 Fault/Error Code?


The following steps can be followed to solve the P0790 fault/error code:

1. Diagnosing the Fault Code: First, an OBD-II scanner should be used to read the fault code recorded by the vehicle's engine control unit (ECU). This is the first step to determine which error the tool is encountering.


2. Checking Electrical Connections: It is important to check the electrical connections in the mode switch and related circuits. Check if connections are loose, corroded or cut. Clear or reconnect connections as necessary.


3. Checking the Mode Button: It is important to check the mode button itself. Does the button work properly? Is there any physical damage or signs of wear on the button?



4. Testing the Mode Button Circuit: A multimeter or appropriate diagnostic equipment can be used to test the mode button circuits. Check whether signals from the mode button are transmitted correctly.


5. Checking the Transmission Control Unit (TCM): It is important to check if the transmission control unit (TCM) is faulty. It may be necessary to test or replace the TCM as necessary.


6. Checking for Software Updates: Software updates may be available in the vehicle's control units. Check if appropriate updates have been installed to fix software bugs or incompatibilities.



7. Replace Parts When Necessary: If the mode switch, TCM, or other related parts are faulty or damaged, they may need to be replaced.


8. Testing the Vehicle: Take a test drive to check if the vehicle's mode switch and shift modes are working properly. This step is important to verify the effectiveness of the actions taken.


All of these steps are general steps that must be followed to solve the P0790 fault/error code. However, depending on the complexity of the fault, further diagnostics and repairs may be required in some cases. Therefore, collaborating with an expert technician or vehicle service is often the best approach.

  



What are the Long-Term Effects of the P0790 Fault/Error Code?

 

The long-term effects of a P0790 fault/error code may vary depending on the severity of the fault, vehicle usage, and timing of the repair process. However, it can often include the following adverse effects:


1. Decrease in Driving Safety: Inability to switch between the vehicle's gear shifting modes or abnormal gear changes can make it difficult for the driver to fully control the vehicle. This can result in a reduction in driving safety, especially in situations requiring sudden acceleration or deceleration.


2. Decrease in Fuel Economy: If the vehicle's gear shifting modes do not work properly, it may negatively affect fuel economy. In particular, if the engine does not operate in the desired mode (for example, in "Eco" mode), fuel consumption may increase.



3. Long-Term Engine and Transmission Damage: Continuously operating the vehicle in the wrong gear mode can cause excessive fatigue of the engine and transmission components. This could lead to engine or transmission damage in the long run and require more serious repairs.


4. Higher Repair Costs: Ignoring the fault code may indicate an underlying problem that could lead to failure of other components of the vehicle that could lead to more serious damage. In this case, higher repair costs may be incurred.


5. Emission Control Problems: In some cases, fault codes can affect emission control systems. Failure of the ECU to function properly may result in the vehicle's inability to control exhaust emissions, resulting in an increase in emission levels.



For these reasons, it is important that the P0790 fault/error code is not ignored and resolved as soon as possible. Repairing the fault code quickly can help minimize long-term effects and ensure the safe and efficient operation of the vehicle.

Comments


bottom of page