The General tab provides core settings for configuring the RM-Primis ECU’s CAN-BUS communication. This is the first step in enabling communication with factory vehicle networks and automatic transmissions, including the ZF 8HP series.
This tab also serves as the gateway to enabling chassis-specific protocols and transmission-specific functionality. In particular, activating the BMW 8HP protocol here will unlock the dedicated 8HP tab, where advanced transmission control options become available.
To begin using the ZF 8HP transmission with the RM-Primis ECU:
BMW 8HP.📂 Once this is set, the 8HP tab will appear at the top of the software. This unlocks full control over:
This option allows you to select the specific CAN-BUS protocol for your vehicle (if needed).
The list of configured protocols allows the RM-Primis to receive CAN-BUS data from several vehicle-specific modules like DASH, ABS, Traction Control, etc., and also provide data over CAN to keep those modules happy when RM-Primis is installed.
Make sure to match the vehicle’s powertrain CAN speed.
⚠️ Using the wrong speed will result in no communication with the TCU or vehicle systems.
Tick this box to activate the internal 120Ω termination resistor:
🧠 Proper termination ensures signal integrity and reliable communication.
Once enabled, the 8HP tab provides full control over the BMW 8HP TCU via CAN-BUS — no third-party programmers or hardware flashing needed.
Choose your desired shift logic mode:
SportSport +ComfortEco📝 Click Store to save the selected mode to the ECU’s configuration.
The RM-Primis can use the TCU-provided output shaft speed to calculate the vehicle speed. Adjust the settings below to match your car:
Enter the physical tire size (e.g. 245/45 R18). This value is used to calculate the rolling circumference and adjust speed readings and gear logic accordingly.
This field shows the calculated circumference in millimeters (mm) based on the entered tire size. You may also input a value manually if using non-standard sizes or unusual tire profiles.
Click this button after changing tire size or circumference to apply the new values to the transmission calculations.
Fine-tune the final vehicle speed reading sent to the TCU or dashboard.
This is useful when calibrating the vehicle for different differential ratios, tire sizes, or when compensating for CAN speed source mismatches.
Use the slider to adjust the correction percentage.
This section provides firmware and identification data directly from the transmission:
Unlocked if control is grantedReads TCU information.
Attempts to unlock the TCU to allow control by the RM-Primis. Based on the information read from the TCU, RM-Tuner will download the right firmware from our server and write it. RM-Tuner will also back up the firmware version data and the coding options.
When running the unlock algorithm it's very important to have a stable power supply to the TCU. RM-Tuner will show you several messages that require confirmation before starting the process – please read and understand them carefully.
⚠️ In case power/communication is lost during the process, the TCU will be bricked.
RM-Tuner has an advanced recovery mode and will try to automatically recover the TCU using the firmware and configuration backups.
In the rare case that automatic recovery doesn't work, please contact us and we will assist you with manual recovery steps.
The 8HP requires a valid final drive ratio to calculate speed correctly.
Accepted values:
2.35, 2.47, 2.56, 2.81, 3.08, 3.15, 3.23, 3.38, 3.46, 3.64, 3.73, 3.91, 4.10, 4.27
While driving, the TCU will calculate the final drive ratio and fit it into one of the above accepted values. It is very important that both the Used Ratio and the Calculated Ratio match. To ensure this, use the Speed Correction slider to adjust VSS.
Current value stored in the ECU.
Automatically determined by comparing wheel speed and output shaft speed.
Clears the current ratio.
Saves the calculated value as the active ratio and applies it to vehicle speed calculations.
This is useful when performing live calibration after differential changes or to compensate for wheel/tire variations.
Displays and manages adaptation values for each clutch pack inside the 8HP transmission.
Each clutch (A–E) shows:
These values are useful for:
Retrieves live data from TCU.
Erases stored values — TCU will relearn adaptively.
💡 The adaptation values are saved when the vehicle stops and the engine is turned off. It's important to use a time delay relay to keep the TCU powered for at least 45 seconds after ignition is off. See wiring diagrams for reference.
The 8HP tab includes two sections:
Covers TCU data, mode, wheel calibration, differential settings, and adaptations (as explained above).
Read and clear stored fault codes:
⚠️ Some DTCs are expected and may not affect performance. We recommend enabling "Clear DTCs on power cycle" in the General tab.
After setting up all the more technical and TCU communication settings related specifically to the 8hp TCU you have to start working on the torque module, to understand how to do that look at the Torque section available torque_table