MTU 20V4000Lx2x Operating Instructions Manual page 122

621 – LO NOx Value
Yellow alarm.
Associated parameter 2.3050.024
Cause
NOx emissions have undershot
the first limit value.
622 – LOLO NOx Value
Yellow alarm.
Associated parameter 2.3050.025
Cause
NOx emissions have undershot
the second limit value.
623 – HI NOx Value
Yellow alarm.
Associated parameter 2.3050.026
Cause
NOx emissions have exceeded the
first limit value.
624 – HIHI NOx Value
Yellow alarm.
Associated parameter 2.3050.027
Cause
NOx emissions have exceeded the
second limit value.
633 – SD P-Ambient Air (HDT2800)
none
Associated parameter 1.0700.087
Cause
Air humidity sensor defect.
122 | Troubleshooting | MS150122/00E 2015-07
Corrective action
1. Check gas quality if feasible.
2. Check gas pressure.
3. Check NOx sensor.
4. Check emissions.
Corrective action
1. Check gas quality if feasible.
2. Check gas pressure.
3. Check NOx sensor.
4. Check emissions.
Corrective action
1. Check gas quality if feasible.
2. Check NOx sensor.
3. Check emissions.
Corrective action
1. Check gas quality if feasible.
2. Check NOx sensor.
3. Check emissions.
Corrective action
u Sensor currently not in standard scope of delivery.