MTU 12V4000M73 series Operating Instructions Manual page 131

Engine does not reach rated speed.
Cause
Engine: Overload.
Air filter clogged.
Fuel prefilter clogged.
Easy-change fuel filter clogged.
Engine cabling faulty.
Injector defective.
Engine speed not stable.
Cause
Injector defective.
Speed sensor faulty.
Engine Control Unit faulty.
Charge-air temperature too high.
Cause
Engine: Overload.
Air inlet temperature too high.
Incorrect engine coolant
concentration.
Intercooler clogged.
Charge-air pressure too low.
Cause
Air filter clogged.
Intercooler clogged.
Exhaust turbocharger defective.
Engine coolant escapes at intercooler.
Cause
Intercooler leaky, major coolant
discharge.
Corrective action
u Reduce load.
1. Check signal ring position of service indicator (→ Page 211).
2. Replace air filter (→ Page 209).
1. Drain water and contaminants from fuel prefilter (→ Page 196).
2. Replace filter element (→ Page 200).
u Replace (→ Page 193).
u Check (→ Page 247).
u Replace (→ Page 185).
Corrective action
u Replace (→ Page 185).
u Check and replace as necessary (→ Instructions for Exchange of
Sub-assemblies).
1. Check plug connections (→ Page 249).
2. Replace Engine Control Unit (→ Page 252).
3. Contact Service.
Corrective action
u Reduce load.
u Check fans and air supply/ventilation ducts for engine room.
1. Check engine coolant level (→ Page 228).
2. Check engine coolant (MTU test kit) (→ Page 236).
u Replace (→ Instructions for Exchange of Sub-assemblies).
Corrective action
1. Check signal ring position of service indicator (→ Page 211).
2. Replace air filter (→ Page 209).
u Replace (→ Instructions for Exchange of Sub-assemblies).
1. Clean compressor wheel (→ Page 203).
2. Replace exhaust turbocharger (→ Instructions for Exchange of Sub-
assemblies).
Corrective action
u Replace intercooler (→ Instructions for Exchange of Sub-
assemblies).
MS150045/03E 2018-08 | Troubleshooting | 129