Scania EMS DTC 4129 SCR - Injection valve for reductant

EMS Engine Management System · Scania · 3 variants

Code 4129 (decimal). Some diagnostic tools show it in hexadecimal as 1021.

In short

Input voltage applied on the OPS3 is unstable

Variant 1: Instable sensor supply voltage

Applies to: EMS10

What does Scania EMS fault code 4129 mean?

What causes Scania DTC 4129?

What are the symptoms?

How to fix Scania EMS fault code 4129?

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Variant 2

Applies to: EMS S6

Variant 3: Requested engine emergency stop

Applies to: EMS S8

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

Code 4129 in other Scania systems

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