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Alientech has released KESS3 Upgrade 3.55, adding OBD and Bench protocols for the Delphi engine ECU fitted to the Isuzu 4JJ1 3.0 litre turbo diesel. Until now these pick-ups were Boot only on KESS3, which meant opening the ECU for every job. From 16 September 2026 the same units can be read and written through the diagnostic port or from the ECU connector on the bench, and the Boot method remains available for units that need it.
Which ECUs
Alientech identifies the family as Delphi 4J, the ECU used on the 4JJ1 3.0 TD engine from 2006 onwards. The OBD protocol reads and writes directly from the diagnostic port. The Bench protocol gives fuller access from the ECU connector for repair and advanced tuning work and, where needed, allows cloning for ECU replacement. Alientech also notes that the OBD protocol is Powergate compatible, so a dealer can deliver files to an end customer remotely without the vehicle coming back to the workshop.
Vehicles this opens up
- Isuzu D-Max 3.0 TD (4JJ1), 2006 onwards
- Holden Colorado 3.0 TD (4JJ1), 2006 onwards
These are the two models named in the release. The Holden Colorado is an Australian market vehicle, so for UK readers the relevant one is the D-Max, a working pick-up that has sold steadily to farmers, builders and fleet operators for two decades. As always, identify the ECU on the vehicle in front of you rather than going by the badge.
What it means
For owners, the 4JJ1 is a common rail diesel that responds well to a remap. The gains that matter on a pick-up are low in the rev range: more torque from just above idle, so a loaded bed or a trailer on the tow bar pulls away without the engine needing to be worked as hard. Driven the same way afterwards, that typically translates into a small but real improvement in fuel consumption as well. Peak power rises too, but on a vehicle like this it is the mid-range shove you notice every day.
For dealers, the move from Boot to OBD changes the economics of the job. A Boot read means removing the ECU, opening it and connecting to the board, which turns a D-Max into a half-day booking. An OBD read is plug in and go, so the same vehicle becomes a quick turnaround while the customer waits. Bench mode sits in between and is the right choice for a suspect ECU, a clone onto a replacement unit, or a vehicle with a damaged diagnostic port. The file service covers the Delphi 4J family, so send us the read and we will return the modified file.
Owners can price a remap for their D-Max in our tuning builder. Dealers can order through the file service, or find out more about KESS3 and the Alientech range if you are not yet running one.
