MTU 16V4000Lx2x Operating Instructions Manual page 114

431 – SS P-Coolant before Engine
Red alarm. Engine shutdown.
Associated parameter 2.0168.922
Cause
Coolant pressure before engine
too low (limit value 2).
Insufficient volume flow, static
pressure too low.
434 – HI T-Coolant before Engine
Yellow alarm.
Associated parameter 2.0173.931
Cause
Coolant temperature before
engine too high (limit value 1).
Engine coolant pump failure,
volumetric flow too low, air in
engine coolant circuit.
435 – SS T-Coolant before Engine
Red alarm. Engine shutdown.
Associated parameter 2.0173.932
Cause
Coolant temperature before
engine too high (limit value 2).
Engine coolant pump failure,
volumetric flow too low, air in
engine coolant circuit.
443 – HI P-Charge Mix Diff.
Yellow alarm.
Associated parameter 2.0183.931
Cause
Difference in mixture pressures
sensed on A and B side is too
high (limit value 1).
445 – SD P-Ambient Air
Yellow alarm.
Associated parameter 1.8004.580
Cause
Ambient air pressure sensor on
ECU faulty.
114 | Troubleshooting | MS150121/00E 2015-07
Corrective action
u Check engine coolant circuit (pressure and flow).
Corrective action
u Check engine coolant circuit (pressure and flow).
Corrective action
u Check engine coolant circuit (pressure and flow).
Corrective action
1. Check throttles for varying positions and malfunction.
2. Check mixture lines for leakage.
3. Check sensors and cabling (B79.22, B79.21).
Corrective action
u Check sensor and cabling, replace as necessary. Fault is
rectified following engine restart.