1A-252 Engine Control System
Symptom Diagnosis Chart 1 (2/2)
LNW21AXF002501-X
EGR system
C-5
Exhaust brake
C-6
Catalyst
D-7
Starter switch
B-2
Starter cut relay
B-4
Starter relay
B-5
Starter
D-13
AP sensor
A-3
Idle position sensor
B-1
VS sensor
A-5
Idle up volume
C-8
Freezer switch
B-3
QWS switch
B-3
Main relay
B-5
A/C switch
B-3
A/C relay
B-6
PTO accelerator sensor
A-4
PTO switch
B-3
Inspect the clutch free system.
Inspect the automatic transmission.
Note: Diagnose the system with the idle stop system
turned off.
Note: Diagnose the system with the idle stop system
turned off. Inspect the clutch free system.
Inspect the system for ASR or AT accelerator cut
request.
Inspect the parking brake or retarder for working.
Inspect the engine oil for proper amount.
Inspect the engine mount.
Inspect the PCV for choke.
White smoke
Large engine vibration
Black smoke
Faulty idling
Easy engine
stall
Short power / poor response /
stumble
Low idle speed
Hunting / instable idling
High idle speed
Switch and relay
Starter system
Stall before warm-up
Stall after warm-up
Unusual sound
Others/notes
PTO
system
Vehicle speed control
system
Exhaust system
No cranking
No initial combustion
Poor startability
Poor startability at
ordinary temperature
Poor startability at
low temperature
Symptom
Check item