Categories
ECU Diagnostics

ECU Diagnostics – part 12 : OSI 7 Layers for Caterham Diagnostics

Communications protocols are often called protocol stacks… they’re layers, or stacks, of different protocols… one layered on top of the other from lowest level (hardware/physical) to highest level (software application). This is where the OSI 7 Layer model comes in… it standardises how we think about the layers and allows us to talk about where […]

Categories
ECU Diagnostics

ECU Diagnostics – part 11 : Logic Analyzer on the CAN Bus

To test out my theories and the code I’d been writing, I needed a simple test and a way to make sure the code (and I) was doing what I thought it should be. The code part was easy, take the JSON files I’d created from the Easimap EC2 file and use it to ask […]

Categories
ECU Diagnostics

ECU Diagnostics – part 10 : Decoding EC2 Files

Now we need to start proving some of our theories about how Easimap is actually talking to the ECU. And it seemed to me that if I was going to prove anything then I’d need to pass a lot of data through any theory I came up with, and that meant writing a program – […]

Categories
ECU Diagnostics

ECU Diagnostics – part 9 : The Easimap Protocol Theory

Ok. so we’ve set ourselves up to be able to look at what is going on with a Caterham diagnostics port, we’ve talked a bit about the theory of what we might see from the port and we’ve also seen that Easimap talks to the ECU using a higher level protocol called ISO 15765-2 (ISOTP). […]

Categories
ECU Diagnostics

ECU Diagnostics – part 8 : Easimap uses ISOTP (sort of)

Ok, that’s enough of the theory about mapping. Lets get back to what Easimap is doing when it talks to the car. When we left this subject last we had got to the point where we could see what Easimap was sending and receiving on the CAN bus, but we didn’t know what it meant. […]