Engine speed not steady
Component
Probable Cause
Task
Fuel injection equip‐
ment
Injector defective
Replace (→ Page 77).
Speed sensor
Defective
Replace.
Fuel system
Not vented
Vent fuel system (→ Page 80).
ECU
Defective
Contact Service.
Charge-air temperature too high
Component
Probable Cause
Task
Engine coolant
Incorrect coolant concentration
Check.
Intercooler
Contaminated
Contact Service.
Engine room
Air-intake temperature too high
Check fans and air supply / ventilation
ducts.
Charge air pressure too low
Component
Probable Cause
Task
Air supply
Air filter clogged
Check signal ring position of service in‐
dicator (→ Page 92).
Intercooler
Contaminated
Contact Service.
Exhaust turbocharger Defective
Contact Service.
Coolant leaks on intercooler
Component
Probable Cause
Task
Intercooler
Leaking, major coolant discharge
Contact Service.
Exhaust gas black
Component
Probable Cause
Task
Air supply
Air filter clogged
Check signal ring position of service in‐
dicator (→ Page 92).
Fuel injection equip‐
ment
Injector defective
Replace (→ Page 77).
Engine
Overloaded
Contact Service.
Exhaust gas blue
Component
Probable Cause
Task
Engine oil
Too much oil in engine
Drain engine oil (→ Page 95).
Oil separator or oil preseparator of
crankcase breather clogged
• Clean preseparator (→ Page 70).
• Replace filter element of oil separa‐
tor (→ Page 71).
Exhaust turbocharg‐
er, cylinder head, pis‐
ton rings, cylinder lin‐
er
Defective
Contact Service.
M015700/06E 2012-06 | Troubleshooting | 55
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