Software Guide – VAG KKL + Fiat ECU Scan Tool with 4-way switch

This cable is used with software such as MultiECUScan (MES) or the older FiatECUScan (FES) for diagnosis, testing, and service on Fiat, Alfa Romeo, and Lancia vehicles. It also works with simpler VAG tools like VCDS-Lite and OBD Auto Doctor in K-Line mode.

Supported Programs

MultiECUScan (MES) – recommended for Fiat/Alfa/Lancia.
FiatECUScan (FES) – older version of MES, still useful.
VCDS-Lite – for basic diagnostics on older VAG cars (K-Line).
ScanMaster ELM / OBD Auto Doctor / Torque Pro – only for generic OBD, not full Fiat functionality.

1️⃣ Install drivers

Connect the cable to your computer (without connecting it to the car yet).
Install the correct USB chip driver:
- FTDI chip: FTDI Virtual COM Port Drivers.
- CH340 chip: CH340 Driver (Windows automatically or via manufacturer's website).
Open Device Manager → Note the COM port assigned to the cable (e.g., COM3).
If desired, you can change the port number to COM1–COM4 to avoid compatibility issues.

2️⃣ Install and configure MultiECUScan (MES)

Download the latest version from www.multiecuscan.net.
Install the program and launch it.
Go to Options > Interfaces:
- Select KL (K-Line) / KKL as the interface type.
- Select the same COM port as in Device Manager.
- Click Test – you should get "Interface OK".
If the test fails – ensure the cable is not yet connected to the car, or try another COM port.

3️⃣ Usage in MES/FES

Set the switch position according to the module's requirements (see hardware guide):
- Mode 1: Engine/ECU – Pin 7 (Standard)
- Mode 2: Airbag – Pin 1 (Yellow adapter)
- Mode 3: ABS – Pin 3 (Green adapter)
- Mode 4: Body/ELPS/IPC – Pin 11 (Red adapter)
Connect the cable to the car's OBD port and turn the ignition to MAR/ON (do not start the engine).
Select the correct car and control unit in MES, e.g.:
- Engine Control Module > No adapter required → Mode 1
- Airbag Control Module > Adapter 1 (yellow) → Mode 2
- ABS > Adapter 2 (green) → Mode 3
- Body/ELPS/IPC > Adapter 3 (red) → Mode 4
Click Connect. MES will display "Connected" when communication is successful.
Perform diagnostics, read/clear fault codes, run tests, or log values.

4️⃣ Usage with other programs

VCDS-Lite (VAG-COM): select "Serial KKL Interface", choose the same COM port.
OBD Auto Doctor / ScanMaster: select "Serial OBD interface", COM port = cable's port.
These programs only communicate on pin 7 (Mode 1).

Common Faults & Solutions

Error Message	Cause	Solution
"Interface not found" / "Test failed"	Incorrect COM port or driver	Install the correct driver and select the right COM port in MES.
"No response from ECU"	Wrong switch position or module selection	Change mode 1→4 until connection is achieved or follow MES instructions.
Communication breaks	USB hub/extension, low power	Connect directly to the computer's USB port without a hub.
Wrong module reached	Incorrect adapter mode	Check the MES module's recommended adapter and set the correct switch position.

Tips & Best Practices

Never change the switch position while the cable is connected to the car – disconnect first.
Turn the ignition to MAR/ON before connecting in MES.
Close other diagnostic programs that might block the COM port.
For coding/adjustments – use stable battery voltage or a charger.