MTU 16V4000L32FNER Operating Instructions Manual page 138

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, flow
too low, air in engine cooling
system.
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, flow
too low, air in engine cooling
system.
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.
138 | Troubleshooting | MS150121/02E 2017-09
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 restrictor flaps for varying positions and malfunction.
2. Check mixture lines for leakage.
3. Check sensors and cabling (B79.22, B79.21) (→ Page 203)
(→ Page 202).
Corrective action
u Replace Engine Control Unit ECU.