JLG 450A_AJ Series II Service Manual - Manual (Page 169)

SECTION 3 - CHASSIS & TURNTABLE
3121290 – JLG Lift – 3-129
• Key On, Engine Running
• System Mode= “Running”
Does DTC 336 reset ?
Intermittent fault
No
Yes
Check wiring and electrical connections
between crankshaft position sensor and ECM
No
Yes
• Poor system ground
• Bad crankshaft position sensor
• Bad ECM
Operate engine at condition
that set fault based on fault
snapshot
Is crank sensor a VR/
magnetic pick-up?
Is the wiring OK?
Faulty wireharness
(twist circuit) Is wiring between sensor
and ECM properly twisted?
No
Does fault only occur at
high operating speeds?
Yes
Increase the air gap between
sensor and trigger wheel
Yes
No
Check wiring and electrical connections
between crankshaft position sensor and ECM
No
Repair wireharness
Yes
• Poor system ground
• Bad crankshaft position sensor
• Bad ECM
Is the wiring OK?
No
Repair wireharness
Yes