Variant 1: Reductant quality too low
Applies to: EMS10
What does Scania EMS fault code 4144 mean?
The measured concentration of the reductant is too low.
What causes Scania DTC 4144?
Poor quality of the reducing agent (too low concentration of reductant) and high NOx tailpipe emissions, simultaneusly. Faulty urea quality sensor [T116] and NOx sensors.
How to fix Scania EMS fault code 4144?
- Ensure that the reductant tank contains reducing agent of the appropriate quality (31-34% urea concentration).
- Check the urea quality sensor.
- Verify that the urea concentration measured by the urea quality sensor agrees with the concentration measured with refractometer.
- Check NOx sensors status.
Variant 2
Applies to: EMS S6
Possible cause
Internal fault in the main unit. The fault may also be due to the fact that the diaphragm pump is blocked or that there is a fault on the diaphragm pump.
System reaction
The fault causes reductant injection to be switched off. The fault affects the vehicle's emissions of nitrogen oxides (NOx) and the lamp which warns about a high level of contaminants comes on in the instrument cluster. A text message is also displayed in vehicles with NOx monitoring. Vehicles with NOx monitoring An active fault code limits the maximum engine torque by approximately 40%. An active fault code cannot be cleared from the control unit. When the fault has been rectified, the control unit must verify that the fault has been rectified in order for the fault code to become inactive.
How to fix
- Check that the diaphragm pump is not blocked or defective.
- If it is, renew the diaphragm pump.
- Switch off the power with the starter key, wait for at least 90 seconds and switch on the power with the starter key again.
- If the fault code is still active, the SCR control unit should be renewed; this means that the main unit must be renewed.
- To verify that the fault has been rectified, the following applies:
- Switch off the power with the starter key, wait for at least 90 seconds and switch on the power with the starter key again.
- If the fault is resolved, the fault code becomes inactive.
- Clear the fault code.
- Switch the power off and on with the starter key three times in succession at 10 second intervals to extinguish the warning lamp.
Variant 3: SCR main unit
Applies to: EMS S8
Detection
Speed of reductant pump too low.
Possible cause
Internal fault in main unit of SCR system.
System reaction
The fault causes reductant injection to be switched off. The fault affects the engine's nitrous oxide emissions. The warning lamp comes on. Vehicles with NOx monitoring The torque is reduced by 40%. An active fault code cannot be cleared from the control unit. When the fault has been rectified, the control unit must verify that the fault has been rectified in order for the fault code to become inactive.
How to fix
- Switch off the power with the starter key.
- Wait for at least 90 seconds and then switch on the power again.
- If the fault code persists, renew the SCR main unit.
- Check that the fault has been rectified as follows:
- Switch off the power with the starter key.
- Wait for at least 90 seconds and then switch on the power again.
- If the fault is resolved, the fault code becomes inactive.
- Then clear the fault code.
- Switch the power off and on three times at 10 second intervals to deactivate the warning lamp.
This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.