DEEP TECHNICAL CONTENT

ODX and CDD diagnostic definitions

ODX and CDD diagnostic definitions: ODX is the XML-based diagnostic-data exchange format standardized as ASAM MCD-2 D and in the ISO 22901-1 family. The page also includes a worked example and measurement sequence.

6 concrete technical facts1 worked example2 sources

Technical frame

ODX and CDD diagnostic definitions: ODX is the XML-based diagnostic-data exchange format standardized as ASAM MCD-2 D and in the ISO 22901-1 family. The page also includes a worked example and measurement sequence.

The technical values here expose the standard, protocol or physical relationship directly; model-specific service values are linked through the matching model/variant dossier.

The goal is not only to define the term but to let the reader calculate and interpret what the data means in a scan, scope or physical test.

Concrete technical facts

  • ODX is the XML-based diagnostic-data exchange format standardized as ASAM MCD-2 D and in the ISO 22901-1 family.
  • ODX can describe diagnostic services, request/response parameters, data-object properties (DOPs), sessions and ECU-variant relationships in machine-readable form.
  • A DOP can centralize bit/byte coding, physical type, unit and computation/decoding information.
  • Package parts such as diagnostic and vehicle information depend on the ODX release and project structure.
  • CDD is Vector CANdelaStudio diagnostic-description format; it is not identical to ODX and conversions require semantic validation.
  • A mismatched diagnostic-description release can interpret DIDs/routines incorrectly even when ECU communication works, so ECU software/variant identity must match.

Worked example

  • Decode example: a 2-byte UWORD raw value of 1250 with factor 0.1 becomes 125.0 physical units; byte order and offset come from the DOP definition.

Data-structure example

raw: 0x04E2 = 1250
factor: 0.1
physical: 125.0

Measurement and verification sequence

  • Match ECU variant/software ID to the diagnostic-description release.
  • Capture raw request/response bytes independently of the description.
  • Verify DID/routine parameter DOP coding/endianness/factor.
  • Cross-check decoded results against an independent OEM/scan value.

Fault-separation logic

  • Is a valid command present and are power/ground/network healthy?
  • Does feedback follow the command?
  • Does an independent physical measurement confirm the output?
  • Is the fault limited to a specific temperature/load/speed condition?
  • Does the result remain stable when the original condition is repeated after repair?

Technical sources

  1. ASAM automotive engineering standards overview
  2. ASAM MCD-2 D (ODX)

Continue investigating

Model-specific real technical data · Measurement references · Technical diagnostic atlas