Scania ALLISON DTC 1821 Gear changing prevention function

ALLISON Allison automatic gearbox · Scania

Code 1821 (decimal). Some diagnostic tools show it in hexadecimal as 071D.

In short

Input signals to the control unit for activation of the gear changing prevention function are incorrect.

Applies to: A4

What does Scania ALLISON fault code 1821 mean?

What causes Scania DTC 1821?

How does the system react?

How to fix Scania ALLISON fault code 1821?

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