Scania MBS DTC 844 Auxiliary heater, too many attempts to start

Q: What does Scania MBS fault code 844 mean?

Auxiliary heater, too many attempts to start. The auxiliary heater does not start, following too many attempts to start. Code 844 (decimal). Some diagnostic tools show it in hexadecimal as 034C.

Q: How to fix Scania MBS fault code 844?

- Check the fuel level. - Check the battery voltage. - Check whether there is air in the fuel lines. - Check the auxiliary heater function using the Workshop Manual for the relevant auxiliary heater.

MBS MBS control unit · Scania

Code 844 (decimal). Some diagnostic tools show it in hexadecimal as 034C.

In short

The auxiliary heater does not start, following too many attempts to start.

Applies to: MBS3 (MBS)

What does Scania MBS fault code 844 mean?

The auxiliary heater does not start, following too many attempts to start.

What causes Scania DTC 844?

- Low fuel level. - Low battery voltage. - Air in fuel lines.

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 as expected.

How to fix Scania MBS fault code 844?

Check the fuel level.
Check the battery voltage.
Check whether there is air in the fuel lines.
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.

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