Common Stg Procedure - JLG 1250AJP Troubleshooting Manual

Note Pretest Instructions
1.377.3 Find component power con-
tacts.
1.377.4
1.377.5

1.378 COMMON STG PROCEDURE

Flash Code: 3-3
Common short to ground procedure. A module input or output pin has been shorted to ground. All driver faults are detected
in a similar manner. Short to ground is detected when the analog feedback reads low and the output is commanded on. See
the fault description for the component or module pin identification. Frequently, this is due to a failed component shorting
ground. This procedure applies to a number of faults so it leaves the determination of specific troubleshooting steps to the
technician. However, it provides guidance to create those steps. Use of the machine schematics is required. Note that power
for a particular component does not necessarily come directly from the battery. For example, the platform module power and
ground circuits use the ground module, but the platform lighting does not. Some components are effectively a separate
module, such as the main boom angle sensors and PVG valves. When opening any electrical connection, inspect the con-
nectors for moisture inside the connector, and pins that are loose, damaged or corroded. Several examples are given start-
ing at 1.178 LT FNT STEER LT STG on Pg. 98.
Note Pretest Instructions
1.378.1 Find component on sche-
matic and on the machine.
1.378.2 Find component power con-
tacts.
3128411
SECTION 1 - FAULT DICTIONARY AND SELECTED TROUBLESHOOTING
Test
Is the component power good? Turn on
machine and check the harness connector
contacts for power. Not all components are
powered by 12VDC.
Is the signal wire good? Check the signal wire
between the component and the signal input/
output on the module. Signal lists start with
section 2.2 BLAM Module Connector Pinouts
on Pg. 215. The information is also on the
schematics. There should only be continuity
between the component and the proper pin on
the module in accordance with the schematic.
There should not be shorts between the wire
and battery + or - terminals, etc. Isolate har-
ness sections that may have a problem by dis-
connecting connectors as needed. Be sure to
check for pins that are damaged, loose or
pushed out of the connector, etc.
Are the other wires good? Check wire from the
component in question ground connection to
the nearest major component. It should have
continuity to the module, swivel or bus con-
nector in accordance with the schematic.
Test
Is the component good? Check the compo-
nent resistance. Resistances of coils are given
in Section 2. Electrical Reference on Pg. 177.
Other loads or sensors should be neither short
nor open. Also, inspect the connector for pins
that are damaged, loose or pushed out, etc.
Is the component power good? Turn on
machine and check the harness connector
contacts for power. Not all components are
powered by 12VDC.
1250AJP
Result Corrective Action
Pass Go to step 1.377.4
Fail Follow power connections back to source check-
ing for power or continuity. Typically, the failure
isn't too close to the battery ground terminal
because then so many things wouldn't work, this
fault would not be detected. Repair as needed
Pass Go to step 1.377.5
Fail Repair as needed
Pass Recheck measurements or try troubleshooting a
different fault. If the component and wiring are
good, reprogram/replace the associated module.
Fail Repair as needed
Result Corrective Action
Pass Go to step 1.378.3
Fail Repair as needed
Pass Go to step 1.377.4
Fail Follow power connections back to source check-
ing for power or continuity. Typically, the failure
isn't too close to the battery ground terminal
because then so many things wouldn't work, this
fault would not be detected. Repair as needed
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