Jaguar S-Type R Plug and Play ECU Project

In 2020 we were approached by Swallows Racing, who had in turn been approached by ‘Megiuars’ the detailing product company, to build a Manual S-Type R. There are various companys that have built up Manual XKR’s with varying levels of success. Using various methods. None of these methods ideal in my opinion. Most were ‘tricking’ the OEM Denso EMS into thinking the gearbox was there and in ‘D’ at all times. The obvious, and most sensible way forward would be to modify the software in the OEM EMS to run the Manual gearbox. All of the S-Type R were Automatic. Many people are used to manual swaps in other Marques, in which a little coding swap, add in a clutch pedal, and bob’s your uncle! That’s not the case for the Jaguar. As the car’s were never available as a Manual car, the manual option is just not available. We worked on the software in the ECU for a while. Probably too long honestly, wasted time. There is very little ‘Source Data’ available for these Denso ECU’s. Being brutally honest, even tuning them well is harder work than it should be. Everything you need to do, except the very basics, needs to be reverse engineered. As you can imagine, putting this sort of work towards a 30 year old ECU, is counter productive.

We decided to take the plunge. Other peoples solutions had been using various ECU’s, with a CAN BOX coupled to it, sending relevent signals to various modules. I’d been using the MaxxECU Range for a few years at this point, I genuinely love the flexibility. We can create our own CAN profiles and add them into the software ourselves. We’d run some of these engines already on the ECU’s. Just making them run the engine was a breath of fresh air. We’d seen various AJV8’s in for tuning on various other brands of ECU. It’s painful at best. Most won’t support the Crank / CAM profiles, so people end up grinding pieces off camshafts! People that don’t want to do this, they essentially just run the engine in wasted spark, and batch fire. Essentially treating the engine as if it was a 4-cylinder. I mean hell, what is this 1995?! Our basic AJV8 package runs fully sequential, runs the fly by wire, dual knock control, dual wideband etc etc. This is just on our basic package. The MaxxECU kicks ass for these engines, and I’m happy it was us that kicked off the MaxxECU – Jaguar pairing.

So we knew we could run the engine, and run the engine well. Box ticked. As I mentioned earlier, the Meguiars S-Type was to be a Manual swap car. We’d be pulling the 6HP gearbox and skipping it, in favour of the 6-Speed Manual, with a Swallows lightweight flywheel and clutch. All these ‘oily bits’ would essentially be all done by Swallows before I got involved. So in this case, we didn’t need to worry about any CAN streams regarding the gearbox.

We decided between Tom (Swallows Racing) and myself to build up a small harness that would fit in the vehicle, to connect the OEM PCM connector, to the new MaxxECU. Essentially a Plug & Play system. We didn’t want to ‘splice’ into anything or add anything that wasn’t required. Lets be fair, all the systems we need to get to are connected to that plug already, so it seemed a reasonable ask. We had a plan. I asked for two cars to be delivered by Swallows to my workshop. The converted Meguiars S-Type, and a working Automatic S-Type R.

The main bulk of the work, would always be the CAN-Structure. We had no idea how the Jaguar Immobiliser (PATS) systems would behave and a whole host of other things. I built up a converter harness to go between our MaxxECU and the Denso connector. We did have to add in one cable to go to the newer style LSU4.2 wideband sensor/s. Optionally the 4.9 if required. There are various systems that are essentially analogue control rather than CAN. For instance the fuel pump. It’s a PWM style single pipe pump to the rail. The fuel rail has a pressure sensor, and the pump is run at varying speeds to maintain the required fuel pressure. The fuel pump high current electronics are located in the rear body module. This is essentially controlled by the ECU. These control circuits. Using an oscilloscope and various other tools, these were identified. and then the correct frequency & duty are replicated as they should be by custom tables in our ECU.

I had the car up and running in reasonble time. Most of the sensors on the engine I already had calibrations for from past projects. For instance the temperature sensors. It was relatively straightforward to get her singing. Everything is working at this point regarding the engine. The OEM throttle body is working perfectly, fuel supply, radiator fans. The whole shooting match.

I now move onto the CAN-BUS system. Every other module in the vehicle does not function as it should. For arguments sakes, the whole instrument cluster is fed from the data provided on the CAN system. Engine temperature, RPM and so on. Fortunately Swallows Racing had dropped me off a stock car. I was able to ‘sniff’ the CAN-BUS system using various tools. I can essentially see what exactly is being sent over the BUS in Hexidececimal. It takes a while to find all the data required. I also had to implement some data to keep the instrument cluster happy. It gives warnings that it can’t communicate with the Gearbox (naturally!).

This is a little video I put together doing the same thing to the Drivetribe XKR. The exact same process is applied in this case: