Purpose

Executes the WWH-OBD ReadDataByIdentifier service. Reads a data record from the ECU.

Format 

        long ndWWHOBDRequestDID (
       TD1 *diagRef,
       unsigned short dataIdentifier,
       unsigned char dataOut[],
       long *len,
       LVBoolean *success);

Input

diagRef

Specifies the diagnostic session handle, obtained from ndOpenDiagnosticOnCANFD and passed to subsequent diagnostic functions. Normally, it is not necessary to manually manipulate the elements of this struct.

dataIdentifier

Defines the data identifier of the data to be read. The SAE J1979DA standard defines the values. Output

dataOut

Returns the ECU data record. If you know the record data description, you can use ndConvertFromPhys to interpret this record. You can obtain the description from the SAE J1979DA 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.

Return Value

The return value indicates the function call status as a signed 32-bit integer. Zero means the function executed successfully. A negative value specifies an error, which means the function did not perform the expected behavior. A positive value specifies a warning, which means the function performed as expected, but a condition arose that may require attention.

Use the ndStatusToString function to obtain a descriptive string for the return value.

Description

The WWH-OBD ReadDataByIdentifier service is based on the UDS ReadDataByIdentifier service (ISO 14229-1).