Battery voltage
Check the battery and alternator.Check the connectors and electrical cables.Proceed as follows to verify that the fault has been rectified:Start the engine and run it at idling speed for at least 15 seconds.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.
What you'll see
No driver-visible symptom recorded.
System reaction
The fault code will not be generated if the engine speed is below 400 rpm to prevent incorrect generation of fault codes when starting. 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 on vehicles with NOx control. Vehicles with NOx controlAn 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 deleted 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.
Diagnostic depth
The battery voltage has been below the permitted level. It has been between 9 V - 21.44 V for 5 seconds.
This is probably due to a fault in the circuit to the alternator or the battery.Another cause could be that current consumption is too high.