Komatsu Fault Code
Free · no signupE15 / CA428
Engine Surging / RPM Fluctuation
Variant 1
System
Hydraulics / Engine
Symptom
Engine Surging / RPM Fluctuation
Diagnosis & fix steps
LOGIC: Water-in-Fuel / Engine Oil Temperature Sensor Circuit Malfunction.
ACTION: Drain water separator bowl immediately. Measure sensor resistance across temperature probe terminals and check wiring harness for rub-through against engine block.
Red Seal field insights
Protect Circuit: Water in fuel causes erratic combustion; ECU limits engine speed to protect high-pressure fuel injectors from galling.
Variant 2
System
Hydraulics / Engine
Symptom
Engine Surging / RPM Fluctuation
Diagnosis & fix steps
LOGIC: Water-in-Fuel / Engine Oil Temperature Sensor Circuit Malfunction.
ACTION: Drain water separator bowl immediately. Measure sensor resistance across temperature probe terminals and check wiring harness for rub-through against engine block.
Red Seal field insights
Protect Circuit: Water in fuel causes erratic combustion; ECU limits engine speed to protect high-pressure fuel injectors from galling.
Variant 3
System
Hydraulics / Engine
Symptom
Engine Surging / RPM Fluctuation
Diagnosis & fix steps
LOGIC: Water-in-Fuel / Engine Oil Temperature Sensor Circuit Malfunction.
ACTION: Drain water separator bowl immediately. Measure sensor resistance across temperature probe terminals and check wiring harness for rub-through against engine block.
Red Seal field insights
Protect Circuit: Water in fuel causes erratic combustion; ECU limits engine speed to protect high-pressure fuel injectors from galling.
Track this across your whole fleet
This code is free to read. AM Fleet Integrity lets your team log fault codes against assets, plus the full fault-code library, QR operator reporting, PM scheduling and predictive alerts. Start free — no credit card required.
Start your free trial