Description of DTC code U0426

In vehicles equipped with control modules, a communication protocol known as CAN bus (Control Area Network) is implemented. It is through this circuit that the controllers are able to communicate and send operating information from the different systems of the car. For the CAN bus, there are two wires known as CAN high and CAN low, through which the data transmission process is carried out.

When the Control Area Network is not working, its two lines have 2.5V but when data transmission begins, the high line becomes 3.75V and the low line drops to 1.25V. Between the two lines, a difference of 2.5V is maintained, which results in avoiding problems for the CAN bus from electric fields or noise.

The establishment of fault code U0426 OBDII occurs when it is detected that the Vehicle Immobilizer Control Module has presented problems when communicating with another controller through the CAN bus, sending information considered invalid.

Symptoms of fault code U0426

  • Check Engine light illuminated.
  • Difficulty starting the engine.

Causes of OBD2 U0426

The reasons why the U0426 OBD2 diagnostic code setting occurs are:

  • CAN bus positive or negative circuits may be deficient.
  • The Vehicle Immobilizer Control Module may have bad wiring or connectors.
  • The Vehicle Immobilizer Control Module may be defective.

Possible solutions of the DTC code U0426

To troubleshoot the DTC U0426 OBDII code you should take into account the following:

  • Consult the TSB.
  • Inspect the state of the CAN bus connections, in order to verify that they do not present deficiencies due to corrosion, burns, or wear.
  • Check the Vehicle Immobilizer Control Module for common damage to the electrical connections. If you detect damage due to high temperatures or friction between the electrical components, proceed with the respective corrections.
  • If even after checking that there is no damage in any of the circuits related to code U0426, it is necessary to determine if the Vehicle Immobilizer Control Module is not damaged. In this case, we recommend that you visit a specialized automotive center.

Codes related to U0426

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