Scania RET DTC 21021 CAN communication from BMS

RET Retarder · Scania

Code 21021 (decimal). Some diagnostic tools show it in hexadecimal as 521D.

In short

Timeout from the brake system when the control unit supply voltage is low.

Applies to: OPC4 (RET)OPC5 (RET2)

What does Scania RET fault code 21021 mean?

What causes Scania DTC 21021?

How does the system react?

How to fix Scania RET fault code 21021?

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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.

Code 21021 in other Scania systems