B4000 SE Cab Plus 4WD V6-4.0L OHV (1997)
Diagnostic Trouble Code Library is a complete listing of all diagnostic trouble codes within the self- diagnostic capabilities of the GEM.
Detecting and Storing Diagnostic Trouble Codes
When the GEM energizes an external device, a short circuit condition can momentarily exist. This fault is not immediately stored as a diagnostic
trouble code since the fault can disappear after a few milliseconds. The GEM repeatedly attempts to energize the device for one second to confirm that
the fault still exists.
If the device is successfully energized before one second elapses, a diagnostic trouble code is not stored and fault management action is not taken. If
the fault continues after the predetermined fault time, a diagnostic trouble code is stored and appropriate fault management action is then taken.
Detecting Faults in the GEM Output Circuits
Battery shorts can only be detected when the device being controlled is actuated. All faults are monitored continuously during the vehicle operation.
Reporting Trouble Codes
Faults are displayed after the continuous DTCs and the on-demand DTCs are retrieved. Continuous DTCs should be retrieved from the GEM before
an On-Demand Self Test is run. These DTCs are then compared against the diagnostic trouble codes retrieved after running an On-Demand Self Test.
Clearing Continuous DTCs
Continuous DTCs must be cleared when the problem has been fixed. Trouble codes can be cleared by sending a request from the NGS to clear them.
Automatically Clearing Codes
Automatic clearing of individual trouble codes is done when the fault is not present for 80 start cycles. These trouble codes are automatically cleared
after 80 start cycles.
Running a Diagnostic Control Test
The tester controls the GEM by performing diagnostic tests. Diagnostic tests are done only when the GEM has disabled the function being controlled.
These control tests allow the tester to control the GEM's outputs and to synchronize the GEM's inputs.
On-Demand Self Test Results
The results of the On-Demand Self Test are in the form of DTCs. The On-Demand Self Test DTC(s) are requested after the test has run.
The On-Demand Self Test detects faults within milliseconds as opposed to one second for the continuous fault code detection. The shorter period of
time reduces the overall test time and can help identify intermittent faults.
Requesting a Parameter Identification (PID)/Data Monitor
For the GEM to detect a battery short, the device must be activated. During Continuous State, a PID may fluctuate between both short and normal
when a battery short is present.
