Why your new or reconditioned injector needs a code

Modern common rail injectors are not identical, even when they come off the same production line. Tiny differences in how each one opens and flows mean the engine computer has to be told how this injector behaves. That information is stored as a calibration code, printed or laser-marked on the injector body. Depending on the manufacturer it is called IMA, ISA or C2I.

What the code actually does

The engine control unit uses the code to adjust the injection quantity and timing for each cylinder. Without the right code, one cylinder can get slightly more or less fuel than the others. The engine still runs, which is exactly why the problem is easy to miss.

When a fresh code is needed

• After fitting a new or reconditioned injector — the old injector's code describes the old injector, not the one you just fitted.
• After swapping injectors between cylinders.
• After replacing the engine control unit, if the codes are not carried over.

Every reconditioned injector we supply comes with its own code, so the fitting garage always has the right one to enter.

What happens if the code is not updated

Typical symptoms are a rough or uneven idle, hesitation, uneven running between cylinders, more smoke, higher fuel consumption and, on some vehicles, warning lights. It also puts extra load on the injectors that are compensating for the difference.

How coding is done

The code is entered into the engine computer with a diagnostic tool that supports the vehicle. Depending on the vehicle it may be learned automatically after a reset, or entered by hand for each cylinder. The exact procedure differs from car to car, which is why we quote strictly from your real VIN. We supply the code; your own mechanic adapts it to the car with their diagnostic tool.

Before you order

Send us your VIN and we will confirm the correct injector for your engine, including the coding requirement. Every reconditioned injector is bench-tested on Bosch/Hartridge equipment before dispatch and comes with a 12-month warranty with no mileage limit.