National Instruments CAN 372139B-01 - Manual (Page 290)

Chapter 6 Automotive Diagnostic Command Set API for C
Automotive Diagnostic Command Set User Manual 6-126 ni.com
ndOBDRequestPowertrainFreezeFrameData
Purpose
Executes the OBD Request Powertrain Freeze Frame Data service. Reads an ECU data record
stored while a diagnostic trouble code occurred.
Format
long ndOBDRequestPowertrainFreezeFrameData(
TD1 *diagRef,
unsigned char PID,
unsigned char nFrame,
unsigned char dataOut[],
long *len,
LVBoolean *success);
Input
diagRef
Specifies the diagnostic session handle, obtained from ndOpenDiagnostic and passed
to subsequent diagnostic functions. Normally, it is not necessary to manually manipulate
the elements of this struct.
PID
Defines the parameter identifier of the data to be read. The SAE J1979 standard defines
the values.
nFrame
The number of the freeze frame from which the data are to be retrieved.
Output
dataOut
Returns the ECU data record. If you know the record data description, use
ndConvertToPhys to interpret this record. You can obtain the description from the
SAE J1979 standard.
len
On input, len must contain the dataOut array length. On return, it contains the number
of valid data bytes in the dataOut array.
success
Indicates successful receipt of a positive response message for this diagnostic service.