U0026 - CONTROLLER AREA NETWORK (CAN) DATA BUS: LOW-SPEED BUS (-) - VOLTAGE HIGH

In the CAN bus or Control Area Network, several controllers are interconnected. They are responsible for transmitting commands through this circuit and operating parameters of the car. The control modules have pre-stored data, which is closely related to the messages needed to be exchanged between serial data circuits.

The Control Area Network uses two dedicated wires to complete the communication. These wires are known as CAN high and CAN low, which carry 2.5 V while the circuit is inactive. During the activation of the bus from the high line, it has 3.75V. The low line decreases to 1.25 volts, maintaining between the two lines 2.5V.

When the diagnostic code U0026 OBDII is set, it means that the low-speed bus has experienced voltages that exceed the range set by the manufacture. So it causes a high voltage condition.

• Check Engine light ON.
• Difficulties when starting the engine.
• Unexpected engine stoppage.

Reasons to set the DTC U0026 OBD2 DTC:

• The low-speed CAN bus circuit may have deficiencies in its wiring or connectors.
• The battery may be damaged.
• A controller may be in bad condition.

To solve the DTC U0026 OBDII code, you must do the following:

• Consult the TSBs.
• Check through an automotive scanner to see if any additional fault codes other than U0026 are stored. If they indicate specific problems with a control module, diagnose them.
• Check the condition of the CAN low-speed bus wiring. Repair or replace any of these that show common damage such as wear or corrosion.