Diagnostic session flow development
Implement and refine diagnostic session sequences around UDS services, with attention to expected transitions, responses, and protected service access.
Vehicle Diagnostics
Implement UDS diagnostic session handling
Diagnostic session handling controls how an application enters, maintains, and leaves the ECU states required by its diagnostic workflow. I implement transitions, keep-alive behavior, response handling, and recovery using the project's session and timing definitions.
Discuss Diagnostic Session DevelopmentProblems I can investigate
Find the behavior behind the symptom
- 01
Unexpected UDS negative response
Investigate negative-response codes that do not match the expected diagnostic flow, using the available problem description, diagnostic data, and ECU behavior.
- 02
Diagnostic session failure
Analyze why an ECU does not enter or remain in the required diagnostic session, including communication sequence, timing, and service availability.
What I can help with
Focused engineering work in Vehicle Diagnostics
Transport and communication integration
Connect diagnostic behavior across ISO-TP or DoIP communication paths and investigate whether transport behavior affects the observed session flow.
Diagnostic data and service handling
Use ODX and PDX information to support DTC, DID, and routine control handling in a diagnostic application or engineering workflow.
Test and automation support
Create repeatable diagnostic tests and analysis workflows with CANoe, CAPL, or DCM where those technologies are part of the target environment.
What to send
Start with the evidence you already have
ECU
The ECU available for communication, testing, or investigation, together with any relevant diagnostic access conditions.
ODX
The diagnostic-data description used to interpret supported services, DIDs, DTCs, or routine control behavior.
PDX
The packaged exchange containing the ODX diagnostic data relevant to the session or application.
Problem description
Observed symptoms, context, reproduction steps, expected behavior, and any known diagnostic session sequence.
How the analysis works
From recorded data to engineering findings
- 01
Review the diagnostic context
Examine the ECU, supplied ODX or PDX data, expected session behavior, and the reported symptoms before defining the engineering scope.
- 02
Trace the session behavior
Compare the expected UDS flow with observed responses, considering ISO-TP or DoIP communication and the availability of diagnostic services.
- 03
Develop or correct the implementation
Implement the required diagnostic application or adjust the relevant diagnostic handling, including session control, security access, DIDs, DTCs, or routine control where applicable.
- 04
Exercise repeatable scenarios
Run defined diagnostic scenarios and assertions using the available engineering environment, then review results against the expected behavior.
What you receive
Deliverables matched to the investigation
Automated test suite
Executable tests with setup, assertions, diagnostic scenarios, and repeatable results for the defined session behavior.
Diagnostic application
Software for executing and interpreting the required ECU diagnostic services, based on the supplied diagnostic data and agreed scope.
Technologies & formats
Automotive data and analysis environments
- Diagnostic Session
Diagnostic Session
An ECU diagnostic operating mode controlling service availability and timing.
- UDS
Unified Diagnostic Services
ISO 14229 diagnostic services for communicating with vehicle ECUs.
- Security Access
Security Access
A diagnostic challenge-response mechanism that unlocks protected ECU services.
- 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.
- DID
Data Identifier
A UDS identifier addressing diagnostic data exposed by an ECU.
- Routine Control
Routine Control
The UDS service used to start, stop, or request results from ECU routines.
- 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.
FAQ
Practical questions before an investigation
- Does entering a diagnostic session unlock protected services?
- Session selection and security access are separate conditions. A service may also depend on ECU state or project-specific prerequisites. The application must use the supplied diagnostic requirements and authorized access mechanism rather than assume that a session change grants permission.
- What is needed to start a diagnostic session development engagement?
- The ECU, relevant ODX or PDX data, and a problem description with observed behavior, reproduction steps, and expected diagnostic flow are useful starting inputs.
- Can you work on an existing diagnostic application?
- Yes. The work can focus on developing, integrating, testing, debugging, or diagnosing a bounded area of an existing diagnostic application or communication setup.
- Can unexpected negative responses be investigated without a confirmed root cause?
- Yes. The investigation can compare expected and observed UDS behavior and narrow likely causes without assuming a root cause before the diagnostic evidence is reviewed.
Discuss the evidence
Discuss Diagnostic Session Development
Share the ECU context, diagnostic data, and observed session behavior to define a focused engineering scope.