Land Rover Injector Coding Guide: Fix Rough Running After Replacement

You diagnosed a bad fuel injector on your Land Rover LR4 or Range Rover Sport (especially the diesel models). You spent hours removing the intake manifold and fuel lines to swap it out.

But when you start the engine, it sounds terrible. It knocks, rattles, and idles roughly. Did you buy a defective part?

Probably not. The problem is that your Engine Control Unit (ECU) doesn't know the new injector yet. You need to perform Injector Coding. Here is how to do it in 5 minutes with the iCarsoft LR V4.0.

iCarsoft LR V4.0 Injector Programmer

The Tool for Professional Diesel Repair

Why Coding is Necessary

Diesel fuel injectors are manufactured with incredibly tight tolerances, but they are never 100% identical. Some flow slightly more fuel, some slightly less.

The manufacturer tests each injector and prints a unique Calibration Code (usually 6, 7, or higher digits) on the top. This code tells the ECU exactly how to adjust the timing for that specific injector to balance the engine.

The Symptom: If you use the old code for a new injector, the ECU sends the wrong fuel amount. This causes cylinder imbalance, knocking noises, and excessive soot smoke.

The Connection to DPF Failure

If your injectors are not coded correctly, the engine burns fuel inefficiently, creating massive amounts of black soot. This is the #1 killer of Diesel Particulate Filters.

If you are replacing injectors because you had DPF issues, make sure you also check our guide on How to Force DPF Regeneration to clean up the mess left by the old injectors.

Step-by-Step: Injector Coding with LR V4.0

Before installing the new injector, write down the code printed on its head. It is very hard to read once installed!

Step 1: Access the Menu

Plug in the LR V4.0. Ignition ON (Engine OFF).
Go to Service > Injector Coding > Land Rover.
Select your engine type (e.g., 3.0L Diesel).

Step 2: Input the Code

Select the cylinder you changed (e.g., Cylinder 1).
The tool will show the current stored code.
Select "Input New Code".
Use the on-screen keyboard to type in the code you wrote down from the new injector.
Press OK / Enter.

Step 3: Confirmation

The tool will display "Write Successful." The ECU now knows exactly how to control the new part. Turn the ignition off for 30 seconds, then start the engine. The idle should smooth out immediately.

Pro Tip: Cylinder numbering on Land Rovers can be confusing (Bank 1 vs Bank 2). Consult a firing order diagram for your specific V6 or V8 engine to ensure you are coding the correct cylinder number.