MTU 12 V 4000 Lx4 Operating Instructions Manual page 135

621 – LO Nox value
Yellow alarm.
Associated parameter 2.3050.024
Cause
Nox emissions have fallen below
the first limit value.
622 – LOLO Nox value
Yellow alarm.
Associated parameter 2.3050.025
Cause
Nox emissions have fallen below
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.
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 is not currently part of standard scope of supply.
MS15027/00E 2013-10 | Troubleshooting | 135