Engine Cranks But Will Not Start - Engine Models; Engine High Idle Inoperative - Engine Models; Engine Low Idle Inoperative - Engine Models - JLG T350 Troubleshooting Manual

1.7 ENGINE CRANKS BUT WILL NOT START - ENGINE MODELS

Step Pretest Instructions
1.7.1
1.7.2
1.7.3 Turn key switch to ground
position and pull the emer-
gency stop
1.7.4 Turn key switch to ground
position and pull the emer-
gency stop
1.7.5 Turn key switch to ground
position and pull the emer-
gency stop

1.8 ENGINE HIGH IDLE INOPERATIVE - ENGINE MODELS

The throttle solenoid engages the engine throttle to high speed. To actuate the throttle solenoid, the Ground Module Engine
Throttle Hold output is turned on continuously while the Ground Module Engine Throttle Pull output is momentarily turned
on, energizing the Engine Throttle Pull Relay to provide higher current to the throttle solenoid while pulling. The Engine
Throttle Hold output remains on during a function and an additional 1 second afterwards, as well as 5 seconds after engine
startup.
Step Pretest Instructions
1.8.1 Turn key switch to ground
position and pull the emer-
gency stop. Engine Running
1.8.2 Turn key switch to ground
position and pull the emer-
gency stop
1.8.3 Turn key switch to ground
position and pull the emer-
gency stop

1.9 ENGINE LOW IDLE INOPERATIVE - ENGINE MODELS

Possible Causes: 4.1.83, 4.1.84, 4.1.85, 4.1.86, 4.1.90, 4.1.89, 4.1.93
3121203
Test
Basic check of likely causes
Does engine start with manual
recoil?
Is X090.87a black wire,
shorted to ground?
Is the Voltage between
X090.86 and X090.85 =
Vbatt?
Is the Voltage onX022.2 =
Vbatt?
Test
Does voltage at X097.2 (Wht/
Yel 48-2-1) = Vbatt momen-
tarily when operating Lift Up?
Does voltage at X091.86 (Wht/
Yel 48-2) = Vbatt momentarily
when operating Lift Up?
Does voltage at X097.1 (Wht/
Yel 48-3) = Vbatt when operat-
ing Lift Up?
T350 T500J
SECTION 1 - TROUBLESHOOTING BY FUNCTION
Result
Yes
No
Yes
No
Yes
No
Yes
No
Result
Yes
No
Yes
No
Yes
No
Corrective Action
Possible Causes: 4.1.83, 4.1.84,
4.1.85, 4.1.86, 4.1.87, 4.1.88, 4.1.91
Possible Causes: Check start motor
wiring, 4.1.4, 4.1.79
Go to step 1.7.3
Go to step 1.7.4
Possible Causes: 4.1.92, 4.1.93
Possible Causes: 4.1.81
Go to step 1.7.5
Possible Causes: Broken Yel/Red 2-3
between X022.2 and X090.86, Broken
black ground wire on X090.85
Possible Causes: Broken Yel/Red 2-3
wire between X022.2 and X009.87, See
3.9 Ignition Relay - Power
Corrective Action
Go to step 1.8.3
Go to step 1.8.2
Possible Causes: Fusible link from B+
to X091.30 broken, Throttle Pull Diode at
X097 Bad, 4.1.80
Possible Causes: Wht/Yel 48-2 wire
from X003.9 to X022.3 or X022.3 to
X091.86 broken, 4.1.10
Possible Causes: Throttle cable froze or
binding, Engine throttle stuck, 4.1.78
Possible Causes: Wht/Yel 48-3 wire
from X003.11 to X022.4 or X022.4 to
X097.1 broken, 4.1.10
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