Scania MBS DTC 850 Auxiliary heater, no flame start

MBS MBS control unit · Scania

Code 850 (decimal). Some diagnostic tools show it in hexadecimal as 0352.

In short

The auxiliary heater detects no flame start.

Applies to: MBS3 (MBS)

What does Scania MBS fault code 850 mean?

The auxiliary heater detects no flame start.

What causes Scania DTC 850?

- Fault in the combustion engine. - There is no fuel or it is contaminated. - Faulty glow plug. - Faulty solenoid valve.

How does the system react?

- The auxiliary heater switches off. - A yellow warning indication is displayed.

What are the symptoms?

The auxiliary heater does not start or stops during operation.

How to fix Scania MBS fault code 850?

  1. Check the combustion engine.
  2. Check whether fuel is missing or contaminants are present.
  3. Check the glow plug.
  4. Check the solenoid valve.
  5. Check the auxiliary heater function using the Workshop Manual for the relevant auxiliary heater.

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

Code 850 in other Scania systems

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