Scania COO DTC 921 Adjustable instrument panel

COO Coordinator · Scania

Code 921 (decimal). Some diagnostic tools show it in hexadecimal as 0399.

In short

The PWM output of the control unit has an open circuit or is short-circuited to voltage, or the voltage on the control unit PWM output is implausibly low.

Applies to: COO8 (COO)COO9 (COO)

What does Scania COO fault code 921 mean?

What causes Scania DTC 921?

What are the symptoms?

How to fix Scania COO fault code 921?

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 921 in other Scania systems

Compare code 921 in every system →