Check that the diaphragm pump is not defective. If it is, renew the diaphragm pump.Pressurise the reductant tank to check that there is no reductant leakage between the reductant tank and the main unit.If there are no leaks: 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.Proceed as follows to verify that the fault has been rectified: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 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