DID read and response testing
Build checks for DID requests, positive responses, negative responses, returned values, and expected diagnostic behavior across defined test conditions.
Vehicle Diagnostics
DID Testing for ECU Diagnostic Data
Test Data Identifier behavior against defined diagnostic expectations, investigate read failures and unexpected UDS negative responses, and produce repeatable evidence for engineering decisions.
Discuss a DID ProjectProblems I can investigate
Find the behavior behind the symptom
- 01
DID read failure
Investigate cases where a Data Identifier cannot be read or returns invalid data, separating diagnostic flow, transport, decoding, and ECU behavior for focused analysis.
- 02
Unexpected UDS negative response
Exercise the expected diagnostic flow and examine negative-response codes that do not match the supplied behavior, session conditions, or diagnostic data description.
What I can help with
Focused engineering work in Vehicle Diagnostics
Diagnostic data interpretation
Use supplied ODX or PDX data to assess DID definitions, expected response structure, and interpretation of diagnostic values without assuming undocumented ECU behavior.
Transport-path investigation
Analyze whether DID test behavior is affected by message transport over ISO-TP or DoIP, keeping transport observations separate from diagnostic service findings.
Repeatable test automation
Develop executable DID checks and assertions using available test environments, with setup and results structured for repeatable engineering review.
Diagnostic flow analysis
Review diagnostic session, security access, and routine control conditions when they are part of the supplied DID test scenario, documenting evidence rather than inferring unsupported behavior.
What to send
Start with the evidence you already have
ODX
The available diagnostic-data description, including DID definitions and expected diagnostic information.
PDX
The packaged exchange containing the relevant ODX diagnostic data and associated assets.
ECU
The electronic control unit available for communication, testing, or analysis.
Problem description
Observed symptoms, context, reproduction steps, and expected behavior for the DID issue.
How the analysis works
From recorded data to engineering findings
- 01
Review the diagnostic basis
Inspect the supplied ODX or PDX data, problem description, ECU availability, and expected DID behavior to define a bounded test scope.
- 02
Define test conditions
Identify relevant diagnostic session, security access, routine control, and transport conditions from the supplied scenario without adding undocumented assumptions.
- 03
Execute and capture checks
Run DID requests and assertions through the available diagnostic setup, recording positive responses, negative responses, returned values, and repeatability.
- 04
Analyze discrepancies
Compare observed behavior with the supplied expectations and examine diagnostic and transport evidence to narrow possible causes.
- 05
Report findings
Document reproducible observations, test coverage, evidence, and open questions in a form suitable for engineering follow-up.
What you receive
Deliverables matched to the investigation
Diagnostic application
Software for executing and interpreting the relevant ECU diagnostic services and DID responses.
Automated test suite
Executable DID tests with setup, assertions, and repeatable results for the defined diagnostic scenarios.
Engineering analysis
A documented technical analysis containing test conditions, evidence, findings, and limitations.
Technologies & formats
Automotive data and analysis environments
- DID
Data Identifier
A UDS identifier addressing diagnostic data exposed by an ECU.
- UDS
Unified Diagnostic Services
ISO 14229 diagnostic services for communicating with vehicle ECUs.
- ODX
Open Diagnostic Data Exchange
An ASAM model for machine-readable ECU diagnostic data.
- ISO-TP
ISO 15765-2 Transport Protocol
A segmented transport protocol for messages carried over CAN.
- DoIP
Diagnostics over Internet Protocol
Diagnostic transport over IP networks as defined by ISO 13400.
- DTC
Diagnostic Trouble Code
A coded diagnostic record identifying a detected fault condition.
- Diagnostic Session
Diagnostic Session
An ECU diagnostic operating mode controlling service availability and timing.
- Routine Control
Routine Control
The UDS service used to start, stop, or request results from ECU routines.
- Security Access
Security Access
A diagnostic challenge-response mechanism that unlocks protected ECU services.
- CANoe
Vector CANoe
A development, simulation, test, and analysis environment for vehicle networks.
- CAPL
Communication Access Programming Language
Vector event-driven language for network simulation, testing, and automation.
- DCM
Diagnostic Communication Manager
The Classic AUTOSAR basic-software module handling diagnostic communication.
- PDX
Packed ODX Exchange
A distributable package containing related ODX documents and assets.
FAQ
Practical questions before an investigation
- What is needed to start DID testing?
- The main inputs are the relevant ODX or PDX data, an available ECU, and a problem description with observed and expected behavior.
- Can you investigate an unexpected UDS negative response?
- Yes. The test can reproduce the defined flow, capture the response, and compare it with the supplied diagnostic expectations and conditions.
- Can DID tests cover different diagnostic transports?
- Where supported by the available setup, testing can examine DID behavior over ISO-TP or DoIP and distinguish transport observations from diagnostic findings.
- Will the testing identify the root cause?
- The work documents evidence and narrows possible causes, but a definitive root cause depends on the available ECU behavior, diagnostic data, and reproduction conditions.
Discuss the evidence
Discuss a DID Project
Share the ODX or PDX data, ECU access, and observed DID behavior to define a focused testing scope.