Scania SC DTC 3121 Internal communication

SC SC control unit · Scania · 6 variants

Code 3121 (decimal). Some diagnostic tools show it in hexadecimal as 0C31.

In short

Faulty communication between internal components in the tachograph.

Variant 1

Applies to: SC1 (TCO)

What does Scania SC fault code 3121 mean?

What causes Scania DTC 3121?

How to fix Scania SC fault code 3121?

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.

Variant 2: Tachograph

Applies to: SC2 (TCO)

Variant 3: Internal fault

Applies to: SC3 (TCO)

Variant 4: Tachograph

Applies to: SC4 (TCO)

Variant 5: Internal fault

Applies to: SC5 (TCO)

Variant 6: Tachograph

Applies to: SC6 (TCO)

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