Ranger Mods

Hi,

are there any known issues to be aware of or avoid when using Forscan with a custom ECU Tune?

Reason I ask is that when attempting to change tyre size in non-Asbuilt, and then do the relearn on the TCM/PCM, it throws up a warning "....IF vehicle is running a custom engine tune, please return PCM to stock firmware BEFORE running this procedure. Please make sure module BCM is configured properly". So now wondering what else I should be aware of? My ECU Tune was done at Ultimate Diesel Tuning.

Only thing close I could find on Forscan forums was this:

"You can use both, no issues.
Forscan makes vehicle option changes.
Tuners change the engine/transmission calibration.

There is one area they overlap, final gear ratio and Tyre sizes, AKA the VID block info.Here is why:

The tune has the option to use the VID block gear ratio/Tyre size, OR those can be specified in the tune itself. But here is the catch: it is one or the other. So if your tuner is setup to use gear ratio from the tune, you MUST adjust it from the hand held device or tuning software.

If your tune setup to use the VID block, you MUST use Forscan or IDS to calibrate the speedometer for gear and/or Tyre size changes. Its is one or the other."

By default VID is enabled (is my understanding).
If your tuner has not altered tyre or diff then it is 'unlikely' they would have touched this setting.
My reading between the lines is that if VID is enabled the setting is defined in the BCM, if VID is disabled the setting is defined in the PCM(ECU).

Happy to have Stewart set me straight.

CatHerder wrote: ↑Sat May 08, 2021 3:21 pm By default VID is enabled (is my understanding).
If your tuner has not altered tyre or diff then it is 'unlikely' they would have touched this setting.
My reading between the lines is that if VID is enabled the setting is defined in the BCM, if VID is disabled the setting is defined in the PCM(ECU).

Happy to have Stewart set me straight.

Thank you. My main issue at the moment is that after changing the tyre size in non-asbuilt, I have not done the relearn and cleared the DTC codes because of the error message - hesitant because of the warning - so trying to understand am I ok to proceed considering that I have a custom ECU tune.??

Now I have also a "Transmission Characterization Update" Showing up under the PCM after the relearn line.?

@saeb Do you have comments on this please?


Sent from my iPhone using Tapatalk

It is a 6 speed which has predefined parameters in the firmware. 6 speed auto does not have provision for relearn, hence why I do not specify TCM relearn for 6 speed on the calculator. 0977 is your max unless I write a custom file to allow otherwise.

3. Run PCM relearn for 6 speed auto or manual transmission and PCM and TCM relearn for 10 speed, this is located at the top of the screen where you selected BCM, IPC module asbuilt etc. from.

How did you go with this Markymark? I am trying to do the same thing, but don't want to lose my custom tune, and cannot go back to stock PCM software.

Have not tried it yet, but just re reading Stewart’s reply above, it should be fine. I am going to also call the shop that did the tune and check with them on the VID issue which will put to rest any concern and give me confidence for not just this but any other mods

Basically any asbuilt change you make in any module will not cause issues with any tune, factory or aftermarket. They are 2 entirely different things, one being the tune (calibration, factory or tuned file) and one being selectable manufacture settings, asbuilt.

If it is regarding tyre size then depending on whether it is a 3.2 or 2.0 is to what you can achieve without changing the firmware.

You as an end user with Forscan will not be able to modify the tune (calibration, factory or tuned file) is any shape or form.

Great news. Thankyou Gentlemen.

All worked Fine. My new tyre size is 275/65/R18, so I set the asbuilt hex to 0977 being the maximum value as Stewart suggested. A couple of things to note.

1. With 0977 set in the tyre size, my GPS actual speed is now about 1-2 klm/hr slower than the speedo indicated speed. Perfect for my liking.
2. When using tyre size caluclators, the hex value given for my tyre size was much larger, but the effect of that would have been an even slower GPS speed compared to indicated. Something a miss in the tyre calculator with newer vehicles?
3. When using the AsBuilt, the process was easy and worked exectly as decribed in all the notes. When using the non-asbuilt, Forscan threw up the warning message from my first post..."IF vehicle is running a custom engine tune, please return PCM to stock firmware BEFORE running this procedure. Please make sure module BCM is configured properly". This appears to be incorrect. Based on this experience I think I will just stick with AsBuilt interface.

It is correct. Speedometer is meant to be 4% different to GPS.

You can see what should be true road speed by going to average speed, set cruise at 100kph and reset average speed. GPS should be 100 and average 100.

In your case it will not be exact.

Average speed is read directly where speedometer has 4% margin.

exactly what i just came here to read ..... im running a dyno tune and was too scared to click the relearn button as well in case it wiped my tune from ecu.

Sirls1 wrote: ↑Sun Oct 03, 2021 8:47 pm exactly what i just came here to read ..... im running a dyno tune and was too scared to click the relearn button as well in case it wiped my tune from ecu.

Forscan cannot wipe a written calibration. Vehicle calibration are totally independent to vehicle programmable parameters which is what Forscan will do.