Scania CMS DTC 644 Hydraulic flow in secondary steering circuit

CMS CMS control unit · Scania

Code 644 (decimal). Some diagnostic tools show it in hexadecimal as 0284.

In short

The dual-circuit steering flow sensor for circuit 2 (T56), connected to pins B22 and B24 on the control unit, indicates that the flow is too low.

Applies to: CMS1 (CMS)

What does Scania CMS fault code 644 mean?

What causes Scania DTC 644?

What are the symptoms?

How to fix Scania CMS fault code 644?

Read the full explanation with Premium

Causes, system reaction, symptoms and step-by-step repair instructions for every fault code are available to Premium members.

  • Full explanations of every code and brand
  • Causes, symptoms and repair steps
  • New brands and codes included
Get Premium – 7,50 € / month I already have an account

Yearly plan: pay 10 months, get 12. Cancel at any time.

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

Code 644 in other Scania systems

Compare code 644 in every system →