National Instruments CAN 372139B-01 - Manual (Page 152)

Chapter 5 Automotive Diagnostic Command Set API for LabVIEW
Automotive Diagnostic Command Set User Manual 5-126 ni.com
status is TRUE if an error occurred. This VI is not executed when
status is TRUE.
code is the error code number identifying an error. A value of 0
means success. A negative value means error: the VI did not
execute the intended operation. A positive value means warning:
the VI executed intended operation, but an informational warning
is returned. For a description of the code, wire the error cluster to
a LabVIEW error-handling VI, such as the Simple Error
Handler.
source identifies the VI where the error occurred.
Output
diag ref out is a copy of diag ref in. You can wire it to subsequent
diagnostic VIs.
DTCs returns the resulting DTCs as an array of clusters:
DTC is the resulting Diagnostic Trouble Code. For the default
2-byte DTCs, you can use
DTC to String.vi to convert this to
readable format as defined by SAE J2012.
Status is the DTC status. Usually, this is a bit field with the
following meaning:
Bit Meaning
0 testFailed
1 testFailedThisMonitoringCycle
2 pendingDTC
3 confirmedDTC
4 testNotCompletedSinceLastClear
5 testFailedSinceLastClear
6 testNotCompletedThisMonitoringCycle
7 warningIndicatorRequested
For OBD, this field usually does not contain valid information.
Add Data contains optional additional data for this DTC. Usually,
this does not contain valid information (refer to DTC descriptor).