UDS Protocol Interview Questions: Automotive

In Automotive Domain, there is a huge opening for the HIL Testers/Validation Candidates and most of the interviewers will ask questions related to Unified Diagnostics Services. So Today I will be listing a few of the questions and answers to the Top UDS Protocol Interview Question with Answers. This is the special request of my friends and well-wishers. So let’s straight away go to the points.

Best UDS Protocol Interview Questions

What is UDS Protocol?

UDS (Unified Diagnostic Services) is an automotive protocol that lets the diagnostic systems communicate with the ECUs to diagnose faults (by modifying/re-writing DIDs and Other ways) and reprogram the ECUs accordingly (if required).

The reason why it is called “Unified” is, it combines and consolidates all the standards like KWP 2000, ISO 15765, and others.

What is the Use of UDS Protocol?

UDS Protocol is used for diagnostic systems, communicating with the ECUs to diagnose faults, and reprogram the ECUs.

What is DTC?

DTC stands for Diagnostic Trouble Codes. A DTC code is a series of diagnostic trouble codes used by a vehicle’s onboard diagnostics (OBD) system to alert you when a vehicle experiences a malfunction. Different DTC codes represent specific problems in your vehicle.

There are two types of DTC:

  • Critical Codes
  • Non-Critical Codes

What are UDS services?

Unified Diagnostic Services is a diagnostic communication protocol used in electronic control units within automotive electronics, which is specified in the ISO 14229-1. It is derived from ISO 14230-3 and the obsolete ISO 15765-3. You can find more details here: Link

What is UDS frame format? Can you please Explain?

UDS protocol is working on the CAN protocol so the maximum 8-bytes of the data can be requested and get to the response in a message like CAN protocol. In the UDS protocol, there are 2-types of frames which are listed below.

  • Diagnostic request Frame (With/without Sub-function-ID).

Again, the Request Frame is divided in the below message format.

  1. Service ID.
  2. Sub-Function ID (optional: not exist for some diag. services).
  3. Data bytes. (DID, Data Rec)
  • Diagnostic Response Frame.

Again, the Request Frame is divided in the below message format.

  • Positive Response.
  • Negative Response.

What are the functions of Diagnostic Services in UDS Protocol?

  • Diagnostic and communication management.
  • Data Transmission.
  • Stored Data Transmission.
  • Input/Output Control.
  • Remote activation of routine.
  • Upload/Download.

Can You Share the few services available in UDS?

  • Diagnostic Session Control (0x10)
  • ECU Reset (0x11)
  • Security Access (0x27)
  • Communication Control (0x28)
  • Tester Present (0x3E)
  • Access Timing Parameter (0x83)
  • Secure Data Transmission (0x84)
  • Control DTC setting (0x85)
  • Response To Event (0x86)
  • Link Control (0x87)

Can You Share few Negative Response Codes available in UDS?

  • 0x12                       Sub-function Not Supported
  • 0x13                       Incorrect Message Length or Invalid Format
  • 0x14                       Response Too Long
  • 0x15 – 0x20        ISO SAE Reserved

What is DoCAN?

UDS protocol is working on the CAN protocol for the communication between the client by request and server by a response to do the diagnostic on the server by request. This is why we call it Diagnostic over CAN (DoCAN).

Latest Top UDS Interview Questions and Answers for 2022.

These are the most asked Questions during Interviews of any Automotive Domain. Still, if you think any Question is missing or anything you want me to add, please do comment below with your query, I will be happy to answer them. Similarly, You can also suggest me another topic which you want me to cover in upcoming articles.

Also Check out: 7 Things You Should Know Before Getting A Perfect Car
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Brajesh Kumar Singh

Brajesh Kumar Singh is the Founder of FeedKnock.com. He love to Write About the Technology, Lifestyle, Fashion and other stuffs. Currently He is working with many Brands to boost Marketing and Handling Digital Marketing Activities. Brajesh has completed his B.Tech from B. P. Poddar Institute of Management and Technology. He is also Helping many NGO's. Little more description about Brajesh Can be found Below Entrepreneur •Social Media Evangelist • Social Media Outreach #Strategist •Digital Marketer •Founder at @ApnaContest @trickdefined @FeedKnock

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