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ZFG Racing's custom tuning process is designed around real-world performance, reliability, and repeatable results—not generic files or one-off adjustments.
This FAQ covers the most common questions about custom tuning, including pre-tune preparation, data logging, supported modifications, troubleshooting, and what to expect throughout the process. Whether you're just getting started or working through a specific concern, you'll find guidance here to help keep things moving in the right direction.
GeneralPre-Tune PreparationPost-Tune SupportGlossaryTroubleshootingModificationsTDN AppSpecial FeaturesFuel & GainsZFG AppDevicesCreditsModel-SpecificAdditional Tunes
This is expected in some cases and can be resolved by following the Additional Steps for Read Vehicle Errors in our TDN Quick Start Guide.
How to Record and Submit a Data Log:
With your device connected to the vehicle's OBD-II port and the engine running:
Open the TDN App → Data Log (paper icon)
Tap START → wait for gauges to appear on your screen
Let the vehicle idle and continue recording for 5 minutes
Tap STOP to end the data log
The app will process the log and display a list of files.
- If you don’t see the file list, go to Data Log →View & Sync Files
- Make sure the file is synced (See: Checking for Synced Files)
How to gather and submit an Info Log:
With your device connected to the vehicle's OBD-II port and the engine on or off:
Open the TDN App → TOOLS / SETTINGS (gear icon)
Tap HELP →Gather Infolog for Support
Tap GATHER INFO LOG and follow on-screen instructions
The app will display a summary screen.
Tap Share and save the file*
Attach the Info Log to your Tune Request
*Note: How to save the file depends on your operating system or app version. You can always email it to yourself then save the .txt file
Any time you have an issue with the TDN App or your device, please try the steps below.
You'd be surprised how many issues are related to the mobile phone or device settings rather than the App!
If none of the solutions below resolve your issue, please let us know.
For fastest service, please include the following information with your inquiry:
At least one previous order number
Device model & generation (e.g., RTD+, RTD4, MPVI3)
A brief description of the issue with screenshots if possible
An info log (instructions here)
Many problems can be fixed by uninstalling and re-installing the TDN App
This is the best starting point for most issues and shortcuts several troubleshooting steps at once (such as app updates, verifying that you're logged into your account, etc.).
While the app is uninstalled:
Forget any existing bluetooth connections to your device (via phone settings)
Clear the bluetooth cache on your tuning device:
Provide power to your device
Press & hold the square button on the front for 10+ seconds (until you see a fast blue flash)
Once the app is re-installed:
Log back into the TDN App
Be sure to use the same login credentials as when tuning was completed
Complete First-Time device setup (TDN App > Tools)
Allow all requested permissions with full access (Precise location, cellular data, wifi, etc.)
Individual things to check
Verify that you are still logged in to your TDN Account (and using the same login as you used for tuning)
Re-sync your device and update firmware
Check for updates (through the App Store and within the TDN App)
Check that your phone has granted appropriate App Permissions to the TDN App
Re-try First Time Setup
Specific issues:
Files not displayed / missing files:
Ensure that you are logged into the correct TDN account (reference previous emails from TDN, or Tune Delivery Network)
Sync Files (TDN App > Flash > Vehicle Folder if applicable > SYNC FILES button)
Required Update for iOS Users (see image below)
The most recent information on troubleshooting TDN-related issues can be found on the HP Tuners website:
HP Tuners Support Search
HP Tuners TDN Guide
Please note: We will make every effort to assist you within our capabilities. However, you may need to submit a help ticket with HP Tuners. In this case, including an infolog (instructions here) with your support ticket is helpful.
HP Tuners also offers live support during normal business hours. To initiate a live chat, please click "Connect With Us" at help ticket link.
We recommend the below steps for outside software and programming errors regarding vehicle identification, such as those encountered in ForScan:
["Unable to Identify the Vehicle - If PCM has a custom tune installed, please enter strategy/calibration name or part number of FACTORY PCM (ex. PC3A-14C204-FGB)"]
1. Flash Back to Your Stock Tune Temporarily
This is the easiest solution and is the method we recommend. Once you have loaded the stock tune to the vehicle, you can restart the software (e.g, ForScan) and save the vehicle profile. This should allow you to load and use the vehicle profile in the future even if the tune has been (re)applied.
2. Check for Software Updates
Such notifications may come up if you’re not using the latest version of the software. Always checking for updates and ensure that you have the latest version installed.
3. Alternative Options
To find the PCM part number, you can visually look at the PCM itself.
You may be able to find it in the As Built Data from motorcraftservice.com/asbuilt
(you are looking for the part number between F118 and /F118, beginning with LB5A for Explorers).
Please note that these solutions do not always work and may not be applicable to all platforms or software systems. Please contact us directly with additional questions.
There are a lot of things to try -- we'll include the common fixes we know of, below.
If none of these work, please let us know and consider submitting a help ticket with HP Tuners. HP Tuners also offers live support during normal business hours, please click "Connect With Us" on the linked page to connect with their support team.
Many issues are resolved by updating your device: (TDN App > Tools > Resync)
Files not displayed / missing files:
Check that you are still logged in to your TDN Account (TDN App > Account)
Ensure that you are logged into the correct TDN account (reference previous emails from TDN, or Tune Delivery Network)
Sync Files (TDN App > Flash > Vehicle Folder if applicable > SYNC FILES button)
For connectivity issues:
Always ensure that your app is up to date (through your phones App Store)
Check for updates (TDN App > Tools > Update Firmware, Update Bluetooth Firmware, Resync, Update Resource files)
Re-try First Time Setup (via TDN App > Setup Device)
Check that your phone has granted appropriate permissions to the TDN App (TDN App > Tools > Set App Permissions)
Required Update for iOS Users (see image below)
If you can't start the data log with your RTD4, or are stuck on "Starting Online Scanning Manger" screen, please try the following:
Provide power to RTD (OBDII with key on/ignition off, or via USB-C)
Open the TDN App, go to Tools, then select "Resync RTD4"
Once re-sync is complete, try data logging again.
If data logging fails, you may need to try resync again (up to 3 times).
If data logging is not successful after your third resync, please head back to Tools, then select "Gather Info Log for Tech Support" and send it to Sales@tunedbyzfgracing.com
It's possible that your custom tune was overwritten - here’s what to do in case Over-The-Air (OTA) updates overwrite your custom tune with a new "stock tune":
1️⃣ Read & sync the new stock tune (READ VEHICLE)
2️⃣ Re-apply your custom tune
> If your existing tunes don’t flash, please submit a Tune Request and briefly explain what happened in the comments, noting that your existing tunes won’t flash.
Note: Some updates may require purchase of a Tune Update — this is rare but not excluded from possibility. Our tuner will indicate if this is required when responding to your Tune Request.
Should I leave OTA updates enabled?
It's 100% personal preference - we don't recommend for or against.

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