OBD Software

When you purchase the OBD II Protocol Stack you will be required to sign an agreement stating you will not sell it to any 3rd party, however, you will be able to use it freely – including all modifications – in your company products.

When you purchase the complete OBD II Protocol Stack you will receive the source code for all the OBD II protocols. The source files are written in C and organised with a layer of abstraction to the hardware specific code so that porting of the code to alternative hardware platforms is kept simple. Currently the design is built and tested using an STM32F103 high density ARM Cortex chip so all the actual calls to this chip and the STM32’s library code are provided too. On top of the stack sits a simple API that attempts to connect to one of the protocols and if successful loops through a file requesting the desired modes and PIDs from the ECU(s).

All our licences come with off-site support. This is phone and email support for any question that your engineers may have about how the software works, porting, or even general questions about OBD II. During your support period you will be notified of bug-fixes if any operational bugs are reported in the software by any of our other clients.

The OBD II protocol stack is licensed for a one-off perpetuity fee. A full licence includes one year off-site support. Contact us for more information.

Our software is undergoing constant testing and not just by us, but also due to the fact it is in daily use by our customers on hundreds of thousands of vehicles. Every week we test approximately 30 vehicles. We try to cover all Year/Make/Model/Engine combinations. With new model years coming all the time this is a continuous task. As the software is coded to the official J1979 standard it does not change much. If we ever add a new feature then a comprehensive verification and validation process is performed. We first test our code on the bench with a selection of OBD II simulators  and then on a range of actual vehicles. We value customer satisfaction and the only time we have seen a communication problem is when there has been a fault on the vehicle. This is why OBD Experts are the industry leaders in OBD II firmware.

The answer is all OBD II compliant cars. OBD II (J1979) is a standard that all manufacturers of vehicles with emissions have to comply with. OBD Experts software works on all vehicles since 1996 in North America and in Europe then it’s all petrol cars since 2001 and all diesel cars since 2004. So is works on GM, Ford, Honda, Chrysler, Toyota, RAM, Jeep, Subaru, Kia, Hyundai, Mitsubishi, Mercedes, Jaguar, Landrover, Volvo, Fiat, Peugeot, Renault, Citroen, Ferrari, BMW, VW etc. etc. Only cars with no emissions i.e. fully electric cars do not need to comply with the J1979 standard and so sometimes do not support OBD II.

Our OBD II software determines the correct protocol for you so you don’t need to worry about protocol detection. However, in case you are interested in knowing more about OBD protocols: OBD II specifies 5 different electrical protocols which can be used to access OBD II information. Automotive manufacturers are required to implement one of the mandated OBD II protocols. In 2008, CAN 15765  became the mandated OBD II protocol for all new vehicles in the US. From 2018, all new vehicles world-wide use the CAN 15765 protocol. Table 1, below, describes which OBD II protocol is favoured by which manufacturers pre-2008. Please note that this list is not exhaustive and that there are always exceptions to these general rules.

One way to tell which OBD II protocol is implemented by a vehicle is by examining the J1962 connector. This connector is often located under the steering wheel on the driver’s side of the vehicle. A J1962 connector is shown below

The numbers in the figure above represent the 16 pins of the J1962 connector. The following J1962 connections are dependent on the protocol(s) in use by the vehicle:

• Pin 2 and pin 10 are used for the J1850 PWM protocol.
• Pin 2 only is used for the GM J1850 VPW protocol.
• Pin 7 is used for ISO 9141-2 and ISO 14230 (KWP2000) communications. Pin 7 is also known as the K-Line. Pin 15 is also known as the L-Line (may or may not be present for these protocols).
• Pin 6 and pin 14 are present for CAN (ISO 15765-4) protocol.
• Pin 16 is Battery Voltage and Pins 4 & 5 are Ground. By checking which pins are implemented in a vehicle it may be possible to determine which OBD II protocol is in use.

You cannot connect microprocessor outputs directly to the J1962 connector on a vehicle. You will require some simple external circuitry including:

• a CAN transceiver
• a voltage boost to 12V for the ISO/KWP lines (this must be weakly pulled up to 12V by a 510 ohm resistor)
• a variable voltage boost for J1850+ (5V for PWM, 7.5V for VPW)
• a boost to 5V for J1850- (this line should also be pulled up to 5V)

Yes! But not using basic OBD II communications. Please click to our Odomatic page to read about this feature in the Odomatic library.

OBDonUDS (J1979-2) is the new standard that extends traditional OBD II (J1979). J1979-2 will be a replacement standard for OBD II in 2027. If you are interested in learning more about OBDonUDS register here for our free webinar and white paper series that begins in Q1 2024.

Yes. If your company has been using an ELM327, STN2120, or an STN1170 in your device and you would like to switch to a different solution then we can help. You can get the same functionality by putting our software into the chip of your choice. You could even save space by adding the OBD functionality to your main processor. Download a white paper on the advantages of switching here or contact us to discuss your options.