Doosan D35S-5 Service Manual page 160

Trouble diagnosis flow when HUNTING is occurred
Idle rotation
hunting (change)
Pump system
Injector system
ECU system
D439E Service Manual
Currently
malfunction
NG
Fuel system check flow
OK
Sensors, wirings check flow
OK
Check SCV resistance value
7.9±0.25Ω(24V), 20℃
OK
Check
injector injection (Diagnosis
equipment) Check the cylinder
with no vibration change at one
cylinder stop mode
OK
Check poor connection of ECU
ground and ECU connector
OK
Erase the
trouble code and previous
pump learned values with the
diagnosis equipment.
Perform the learning again at idle
with no load after engine
warm up.
Currently
malfunction
Check based on
each trouble code
Hunting
corrected?
NG
NG
NG
NG
Repair or correct the wiring
and connection
OK
NG
158
Ex)
Fix the single fall of sensors,
ECU, pump SCV and TWV
system
CKP (Crankshaft Position)
Sensor system
PC sensor system (rail
pressure sensor)
Accel sensor system
ECU sensor system (CPUI
malfunction)
Pump SCV system
TWV system
Defect caused by FCCB (fuel
control for cylinder balance) is
processed by other flow
OK
Completed
Replace supply pump
NG
Check injector
wiring
OK
Complete
Complete
Replace ECU
Repair or replace
wiring
4. Fuel system