Check that there is already some reductant in the tank and that it is not frozen.Check whether the vent to the reductant tank is blocked.Check whether lines or connections are leaking or are blocked.Check whether the prefilter, main filter or filter in the combined tank unit is blocked.Check that heating of the reductant tank is working.Check that the reductant doser closes completely.If the fault is in the main unit, the main unit must be renewed.Carry out the system checks that are available in SDP3 for the SCR system. The system checks can help to detect some of the above faults.Proceed as follows to verify that the fault has been rectified:Carry out the test "Devalidating fault codes for NOx control" which can be found under the Check tab in SDP3 to check that the fault has been rectified. The test should be carried out outdoors because the exhaust gases become very hot and there is a risk that the exhaust extractor hose will melt. The test may take between approximately 5 to 30 minutes to carry out, depending on which fault codes are active.Otherwise, carry out the following so that the control unit will devalidate the fault.Start the engine and switch it off.If the fault has been rectified, 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.

Diagnostic depth