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9)
ANALYSIS OF GRAPHIC SMART DISPLAY RELATED ALARMS
(1)
Graphic Smart Display alarms
WATCHDOG
Cause:
At start-up the watch dog signal is already active before the software has generated it. At standby
or running condition the watch dog signal is not active (in alarm status).
Troubleshooting:
The WD hardware circuit or microcontroller output port are damaged. In both cases no external
component are involved. Replace the logic board.
COIL SHORTED
Cause:
This alarm occurs when there is a short circuit of the AUXILIARY coil connected to CNB#1
output. After the overload condition has been removed, the alarm exits automatically by releasing
and then enabling a travel demand.
Troubleshooting:
A) The typical root cause for this error code to be displayed is in the harness or in the load coil.
So the very first check to carry out concerns connections between dashboard outputs and
loads.
B) In case no failures/problems have been found externally, the problem is in the logic card, which
has to be replaced.
DRIVER SHORTED
Cause:
The driver of the auxiliary electro valve coil is shorted.
Troubleshooting:
A) Check if there is a short or a low impedance pull-down between NAUX (CNB#1) and -BATT.
B) The driver circuit is damaged in the logic board, which has to be replaced.
AUX DRIVER OPEN
Cause:
The AUX coil driver is not able to drive the load. The device itself or its driving circuit is damaged.
Troubleshooting:
This type of fault is not related to external components; replace the logic board.
HARDWARE FAULT
Cause:
At key-on the dashboard checks if the AUX driver is turned off by a not active (alarm status)
watch-dog signal. If it is not turned off then the alarm is generated.
Troubleshooting:
The problem is inside the logic, no external component are involved, replace the logic board.
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