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| validation engineer questions |
1. Can you brief about 31 service ID with subfunctions
The RoutineControl (0x31) service in the UDS protocol allows the tester to start, stop, or request the results of a routine on an ECU.
The RoutineControl service is helpful in performing various diagnostic tasks on the ECU, such as:
- Erasing fault memory.
- Programming or reprogramming ECU memory.
- Testing or checking of RAM or ROM memory.
- Testing ECU inputs or outputs.
- Checking ECU calibration or configuration.
- Performing self-tests or functional tests.
- Activating or deactivating certain functions or features of the ECU.
- Reading or writing calibration or configuration data from or to the ECU.
Preconditions:
- The engine should not run (Engine speed)
- The vehicle should not be moving (Vehicle speed)
- The immobilizer should be unlocked
- OEM or supplier-specific condition (vary from OEM to OEM)
- Each routine pre-condition would change (based on customer req)
- Extended diagnostic session or customer. Specific session
Subfunctions in 31 SID
01 - Start RID
02 - Stop RID
03 - Request RID result
Examples for Diagnostics
starting RID
Tx:- 31 01 F1 10
Rx:- 71 01 F1 10
Explanation:- 31 SD, 01 subfunction, F1 10 example RID, +40 will add to SID for the positive response so 71 will come
stopping RID
Tx:- 31 02 F1 10
Rx:- 71 02 F1 10
request RID result
Tx:- 31 03 F1 10
Rx:- 71 03 F1 10 01
In the request result, we have several states of RID which are
01: routine is running.
02: routine is finished successfully.
03: routine is finished with error(N_OK)
04: routine is stopped
Negative Responses:
without starting any RID, if we try to stop RID we will get NRC 24
Tx: 31 02 F1 10
Rx: 7F 31 24 -> request sequence error
Tx: 31 01 1F 01 -> starting unsupported RID
Rx: 7F 31 31 -> request out of range
Without unlocking the ECU if try to start any RID we will get NRC 33
Tx: 31 01 F1 10
Rx: 7F 31 33 -> security access denied
2. What is the DLL algorithm for the received key value?
The algorithm for calculating the received seed key value using a DLL file would depend on the specific implementation of the DLL file. Without access to the specific DLL file and its implementation, it is not possible to provide a detailed explanation of the algorithm. However, in general, a seed key value calculation algorithm might involve the following steps:
Initialization: Initialize any necessary variables or data structures required for the calculation.
Inputs: Retrieve the necessary inputs and parameters required for the calculation, such as the seed value, the encryption key, and any other data required by the algorithm.
Calculation: Perform the calculation of the seed key value using the inputs and parameters, using a mathematical function or algorithm. The specific details of the calculation would depend on the specific implementation of the DLL file.
Output: Return the calculated seed key value as the algorithm's output.
3. Explain about CAN communication time out?
A Controller Area Network (CAN) timeout will occur when a node in the network does not receive a response from another node within the specified time frame. The time frame is defined by the node's configuration and can be set to a specific value, such as 50ms, 100ms, or more.
A CAN timeout can occur due to several reasons, including:
Communication Failure: A communication failure between nodes can cause a timeout. This can be caused by a faulty cable, a broken node, or an overloaded network.
Bus Congestion: If the bus is congested with too much traffic, messages may be delayed, resulting in a timeout.
Incorrect Configuration: If the time frame for the timeout is set too short, a timeout may occur even if the communication between nodes is working correctly.
Malfunctioning Node: A malfunctioning node, such as a sensor or actuator, can cause a timeout if it does not respond within the specified time frame.
It is essential to detect CAN timeouts and identify the root cause to prevent potential problems and improve the reliability of the system.
3. Can you discuss the various types of ECUs in a vehicle and their functions?
- Engine Control Module (ECM) - This ECU is responsible for controlling the engine's performance, including fuel injection, ignition timing, and emissions control.
- Transmission Control Module (TCM) - The TCM is responsible for controlling the automatic transmission, including shifting and torque converter lock-up.
- ABS Control Module - The ABS control module manages the Anti-Lock Brake System, helping the vehicle maintain stability and control during braking.
- Airbag Control Module - The airbag control module manages the deployment of the airbags in the event of a crash.
- Body Control Module (BCM) - The BCM controls various body functions, such as power windows, door locks, and lighting.
- Chassis Control Module - This ECU manages suspension, steering, and braking systems to improve handling and stability.
- Powertrain Control Module (PCM) - The PCM integrates the functions of the ECM and TCM, managing the overall powertrain system.
- Telematics Control Unit - This ECU manages the telematics and infotainment systems, including navigation, audio, and communication functions.
- Open CANoe software and create a new project or open an existing project.
- Go to the "View" menu and select "Panels."
- Click on the "New Panel" button.
- Enter a name for the panel in the "Name" field.
- Select the type of panel you want to create (e.g., Classic, Modern, etc.).
- Add the desired widgets, such as buttons, gauges, displays, etc. to the panel.
- Configure the properties of each widget as desired.
- Save the panel by clicking on the "Save Panel" button.
- The panel is now available for use in the project and can be opened from the "View" menu.
- Start CANoe and open the configuration you want to log.
- Go to the "Measurement" menu and select "Log Configurations".
- In the Log Configuration window, select "Create Log Configuration".
- In the "Create Log Configuration" window, enter a name for the log configuration and select "HTML" as the file format.
- Select the channels and signals that you want to log. You can also specify the logging rate and the length of the log.
- In the "Output" section, specify the location where the log files will be saved.
- Click "OK" to close the "Create Log Configuration" window.
- Start the measurement by clicking the "Start Measurement" button in the CANoe toolbar.
- The HTML log files will be generated and saved in the specified location once the measurement is complete.
- Open the CANoe software and create a new project or open an existing project.
- Connect the ECU to the CAN bus network and configure the necessary settings in CANoe, such as the bus parameters and the ECU node properties.
- Go to the "Measurement" menu and select "Setup Measurement."
- In the "Measurement Setup" dialog box, select the "Time" tab.
- In the "Time" tab, select the signals that represent the switch-on and switch-off events for the ECU.
- Start the measurement by clicking on the "Start Measurement" button.
- Observe the signals in the "Time" tab to determine the switch-on and switch-off times for the ECU.
- The switch-on time can be measured as the time between the ECU receiving power and the first relevant signal being transmitted, while the switch-off time can be
- measured as the time between the last relevant signal being transmitted and the ECU losing power.
7. Can you explain what is CANOE tool and its purpose?
CANOE (Controller Area Network Analyzer) is a tool used for testing and analyzing communication networks in the automotive industry. It is used to simulate and monitor Controller Area Network (CAN) and other in-vehicle communication networks such as FlexRay and LIN. The purpose of CANOE is to aid in the development, testing, and validation of the communication networks and the electronic control units (ECUs) connected to them, ensuring that the network operates as intended and without any faults or errors. CANOE provides features for message and protocol analysis, network simulation, and data visualization, making it a valuable tool in the automotive development process.
8. What is HIL testing and why is it important in the automotive industry?
HIL testing entails simulating vehicle and environmental inputs for the electronic control unit (ECU) under test, causing it to believe that it is reacting to real-world driving conditions on the open road. The HIL bench contains all of the relevant vehicle components. A simulator presents inputs to actual cameras and radar systems, which in turn send signals to the system under test to see whether it responds correctly to the inputs.
9. What is a bootloader and its functions in ECU?
a bootloader is a specialized software component that plays a crucial role in the management and updating of the ECU's firmware or software. The term "bootloader" is derived from "bootstrap loader," which historically referred to a small program that initiates the loading of a larger program or operating system.
The primary functions of a bootloader in an ECU include:
- Firmware Update
- Code Integrity and Authentication
- Recovery and Redundancy
- Communication Interface
- Partitioning and Memory Management
- Verification and Testing
- Configuration and Initialization
- Compatibility and Version Control
10. What is the ECU state if no software was installed?
When an ECU has no software, it's like a blank piece of paper with nothing written on it. It doesn't know what to do or how to work because it doesn't have the important instructions it needs. and it doesn't communicate with others and it can't fix or control anything because it doesn't have the right things inside.
11. What is +ve suppress bit or alive bit?
Service ID 3E means Tester Present This SID is used to provide a time delay and to make nondefault sessions alive. In this we have 0x00 and 0x80 are the subfunctions.
whenever the tester is in any session except the default session after 5 seconds that session will expire and the ECU will move to the default session to avoid that we are using 3E SID.
Tx: 3E 00
Rx: 7E 00
8 4 2 1 8 4 2 1
Bits: 0 0 0 0 0 0 0 0
Suppose if we are sending a command like that always we are getting unnecessary +ve response continuously. if we are getting always responses like that BUS load will increase.
so to reduce that BUS load we are doing
8 4 2 1 8 4 2 1
Bits: 1 0 0 0 0 0 0 0
Tx: 3E 80 then ECU will never provide unnecessarily +ve response. so making the 7th bit 1 is called suppress bit.
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