JLG G12-55A Service Manual - Manual (Page 182)

Electrical System
9-40 G10-55A, G12-55A
9.13 TROUBLESHOOTING - JOHN DEERE
9.13.1 Engine Fault Codes Retrieval
1. Park the machine on a firm, level surface, level the
machine, fully retract the boom, lower the boom,
place the transmission control lever in (N) NEUTRAL
and engage the park brake.
2. Turn the ignition switch to “ON”.
3. Push down and hold the Reset button on the dash
for 3-5 seconds. The fault lamp will begin to flash a
code number.
The light will flash the first digit then pause for a
short time and then flash the second digit. If there
are “active” codes, the system will first flash code 32.
If there are no “active” codes, the system will flash
code 88. The system will then flash code 33 if there
are any “stored” fault codes. If there are no “stored”
codes, the system will flash code 88.
4. Once the code is retrieved, turn the ignition OFF.
Note: When the engine sensor inputs exceed normal
operating ranges, the ECU will derate the amount of fuel
that is delivered to the engine. A fault code will always
accompany a fuel derate. If the engine is running at a
much lower rate, check the fault codes first to see if the
engine is experiencing an internal problem.
9.13.2 Engine Fault Codes Chart
Fault Codes SPN Codes FMI Codes Definition
11 N/A N/A Analog Throttle (A) Input High
12 N/A N/A Analog Throttle (B) Input High
18 110 3 Engine Coolant Temperature Input Voltage High
19 110 4 Engine Coolant Temperature Input Voltage Low
21 620 3 Sensor Supply Voltage High
1079 3 Sensor Supply Voltage High
22 620 4 Sensor Supply Voltage Low
1079 4 Sensor Supply Voltage Low
23 100 3 Engine Oil Pressure Input Voltage High
24 100 4 Engine Oil Pressure Input Voltage Low
25 105 3 Manifold Air Temperature Input Voltage High
26 105 4 Manifold Air Temperature Input Voltage Low
28 629 13 ECU Error
32 N/A N/A Signifies Start of Active Fault Codes
33 N/A N/A Signifies Start of Previously Active Fault Codes
37 174 3 Fuel Temperature Input Voltage High
38 174 4 Fuel Temperature Input Voltage Low
39 637 2 Crank Position Input Noise