WinOLS Mastery: Map Identification & Editing: ECM Read and Write Options
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ECM Read and Write Options
04.47
| 00:00 | - Obviously reading and writing the calibration to the ECU is a big part of tuning using WinOLS but there are a few different ways of performing this task and there are some pros and cons associated with each. |
| 00:12 | Conventionally, with commercial reflashing solutions from the likes of HP Tuners, we access the ECU via the OBD2 port and this is certainly convenient from the tuner's perspective. |
| 00:22 | This process however will only read the tune data from the ECU. |
| 00:27 | That's OK on one hand because this is obviously the area of the file that we want to make our calibration changes to. |
| 00:35 | If something goes wrong during an OBD2 read or write however, there is a small chance that the ECU can become unresponsive or bricked as it's usually referred to. |
| 00:45 | Recovering a bricked ECU if we only have an OBD2 read can be problematic or in some cases impossible, requiring an expensive replacement ECU. |
| 00:55 | Another possibility is performing what's referred to as a bench read where we connect jumpers directly to the ECU header pins. |
| 01:03 | The advantage of this is what we're performing a full read on the ECU and not just receiving the tune data. |
| 01:10 | There will also be a host of other information contained in the read such as immobiliser data for instance. |
| 01:15 | This means we have a full read of everything inside the ECU which means we should be able to recover a bricked ECU if something does happen to go wrong. |
| 01:23 | Since we're not relying on the car's electrical system when we're bench flashing, the voltage supply, which is one of the more common reasons for flashing failures, is also more consistent and reliable, removing this as a source of worry. |
| 01:37 | The downside of a bench read is that we need to physically access the ECU in order to do this which can range from straightforward to fiddly and time consuming. |
| 01:46 | The third option of flashing the ECU is directly to the PC board in what's referred to as background debug mode or BDM for short. |
| 01:54 | This is the same technique the OE manufacturers use to write to the ECU during manufacturing and a big advantage is that it's incredibly fast. |
| 02:03 | We're talking seconds here potentially instead of several minutes. |
| 02:07 | The downside here should be pretty obvious though, as it requires the ECU case to be carefully prised open and then we need to access specific pads on the PC board. |
| 02:17 | Tuners who use this BDM flash method will usually have a specific jig or fixture to make contact to the correct locations on the PC board during the read and writing process. |
| 02:28 | Even once you've flashed the ECU, there's still the challenge of properly sealing the ECU case before reinstalling it in the vehicle. |
| 02:36 | With modern ECUs now being located normally in the engine bay where they're exposed to the potential for moisture ingress, sealing the ECU case properly is critical to the long term reliability of the ECU. |
| 02:48 | The reality is that in some instances, OBD2 and bench flashing is just not an option however and some ECUs will require BDM flashing so this is something you'll need to be prepared for, depending on what vehicles you want to support. |
| 03:03 | Another challenge with some modern ECUs is that we can't actually read the file out of the ECU and instead the interface that we're using will retrieve some information about the ECU, the vehicle and software version, before downloading a stock or base file for that ECU from the internet. |
| 03:20 | This means that if you're dealing with a tuned vehicle, you're not going to be able to actually retrieve the tuned file and instead you'll be starting from stock. |
| 03:28 | This sounds like a potential downside but as you'll find out as we move through this course, we highly recommend always ensuring you're starting with a completely stock file, prior to making any tuning changes so this ensures that we're not working from a modified file. |
| 03:44 | The reason we want to start with a stock file is twofold. |
| 03:46 | First of all, OLS always compares our current version to the original which allows us to easily see what changes have been made, what magnitude the changes are and also to revert to stock easily and quickly if required. |
| 04:01 | More importantly though, this ensures that we're not going to be working with a file that has fundamental errors baked into it by the last tuner. |
| 04:09 | While there are obviously some excellent tuners providing quality calibrations that have been properly developed, sadly the majority of tuners in the industry don't understand what they're doing and the quality of their work is questionable at best. |
| 04:23 | Let's just have a quick recap before we move on. |
| 04:26 | When it comes to reading and writing the contents of the ECU, we have the option to do this from the OBD2 connector, directly from the ECU header, or directly from the PC board using the BDM method. |
| 04:38 | Each has its pros and cons and not all options will be applicable to every ECU. |
