U1120 Code failures by brands


Description of DTC code U1120

The Controller Area Network, known as CAN bus, is a communication system established by the various control modules and other electronic devices installed in the automobile. The information shared and received by these controllers can be complementary to other systems.

With the CAN bus system, each computer can communicate with the other controllers connected by this circuit without the need for complex wiring. A control module can prepare and transmit sensor information, and send it over the CAN bus (CAN low and CAN high) and the receiving controller can check this data and decide whether to ignore or accept it.

The PCM (Powertrain Control Module) receives electrical signals with which it is informed of the vehicle's speed. This information is transmitted over the C bus of the Controller's Area Network from the ABS Module (Anti-lock Braking System). In case the Powertrain Control Module does not receive such a signal, it will be considered a trip fault and the diagnostic code U1120 OBDII will be set.

Symptoms of fault code U1120

Causes of OBD2 U1120

U1120 OBD2 fault code is set when one or more of the following occurs:

  • The Anti-lock Brake System Module (ABS) wiring may have common deficiencies.
  • The ABS Control Module electrical connections could be damaged.
  • A Speed Sensor may be in poor condition.
  • The Anti-lock Brake System Module could be defective.

Possible solutions of the DTC code U1120

To troubleshoot the DTC U1120 OBDII code you should consider the following:

  • Consult the Technical Service Bulletins.
  • Verify if additional DTCs to U1120 are configured, paying more attention to those that indicate specific faults of the ABS Module or any Speed Sensor. Correct these codes.
  • Check the anti-lock brake system module harness for bad wires or connectors. Likewise, check to see if the voltages on this circuit match those specified by the manufacturer. If any inconsistencies are found, make the appropriate repairs.
  • If you rule out electrical faults, suspect damage to the ABS module. In this case, go to an advanced automotive center.

Codes related to U1120

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