Fault code: 4105 SCANIA

Error identification:

The SCR control unit has no CAN message from the NOx sensor.

Cause:

Communication between the NOx sensor and the SCR control unit is not working.

If the fault code has occurred once, it may be because the NOx sensor has been renewed.

If the fault code recurs, it is probably a fault in the voltage supply to the NOx sensor, the NOx sensor, harness-to-harness connectors or electrical cables.

Notes:

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% after the engine has been running for 50 hours.

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.

Action:

Check the electrical cables of the circuit and clean the harness-to-harness connectors.

If this does not help, check that the SCR control unit receives 15 voltage and that there is voltage supply to the NOx sensor control unit.

If this does not help, renew the NOx sensor.

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 3 times in succession at 10 second intervals to extinguish the warning lamp.