Scania DCU DTC 786 H-bridge front door leaf, error message

DCU DCU control unit · Scania

Code 786 (decimal). Some diagnostic tools show it in hexadecimal as 0312.

In short

While monitoring hardware functions, the H-bridge driver stage has detected an internal fault. The door motor is associated with CN2-17 and CN2-13.

Applies to: DCU3 (DCUA)DCU3 (DCUF)DCU3 (DCUM)DCU3 (DCUR)

What does Scania DCU fault code 786 mean?

While monitoring hardware functions, the H-bridge driver stage has detected an internal fault. The door motor is associated with CN2-17 and CN2-13.

What causes Scania DTC 786?

- Short circuit in cable harness to motor. - Too high a current to the motor. - Open circuit in cable harness.

How does the system react?

- The door control unit signals the fault via the CAN network to the main body system (MBS). - An error message is activated and a lamp with an exclamation mark lights up in the instrument cluster for the affected door on the bus stop side.

What are the symptoms?

The door leaf stops.

How to fix Scania DCU fault code 786?

  1. When the door stops, press the door button to start the door again.
  2. If the fault persists: try to restart the door control unit by switching it off and on again.
  3. Cut the voltage supply to reset the door control unit by:
  4. Unplug the connector connected to CN1 or - remove the fuse for the voltage supply to pin CN1-1.
  5. Connect the connector or replace the fuse and check the operation of the door.
  6. Check the cable harness.
  7. Check the connector.
  8. If the fault persists: renew the door control unit.

This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.

Code 786 in other Scania systems

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