Description of DTC code U0401

The various control modules installed in modern vehicles are interconnected through a complex wired network known as the Control Area Network (CAN). All operating information is continuously exchanged because of this network, as well as the commands that affect the operation of the car. In some cases, there are modules that are programmed to wait for certain information related to another module.

The PCM (Powertrain Control Module) not only acts as an information exchange center but also monitors that the information exchange system sent and received by the modules is working properly. If it detects a communication failure between two or more modules over a period, the fault code U0401 OBDII will be set.

Symptoms of fault code U0401

  • Check Engine light ON.
  • Ignition problems.
  • Loss of engine power.
  • The activated fail-safe mode in the transmission.
  • The Anti-lock Braking System (ABS) does not work.

Causes of OBD2 U0401

The reasons for setting the U0401 OBD2 diagnostic code are:

  • There may be damage to the wiring or connectors, causing an open or short circuit.
  • On certain vehicles, if a sensor is defective, this code will be set. In these cases, defective sensors will be indicated by specific codes.
  • A control module may be in bad condition.

Possible solutions of the DTC code U0401

To solve the DTC U0401 OBDII code, take into account the following:

  • Consult the TSBs and check if there are other fault codes If this is the case, make notes of the order in which they were stored and resolve them according to that order.
  • Thoroughly check all wiring and connectors related to the system. Repair or replace as appropriate.
  • Make resistance, ground signal, continuity, and reference voltage tests on the circuit wires. The values obtained should be compared with those indicated by the manufacturer, and if you find big differences concerning those expected, make the necessary repairs.

Codes related to U0401

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