Recreating Unobtainable Diagnostic Tools For The Jaguar XJ220

If you own a Jaguar XJ220 or the rarer XJR-15, you’re probably not short on money or real estate. You may, however, be finding it hard to lay your hands …. Recreating Unobtainable Diagnostic Tools For The Jaguar XJ220.

You may, however, be finding it hard to lay your hands on a diagnostic tool that is compatible with the ancient Zytek ECU. Thankfully, [Tom Radom], is working to change that. As the owner of XJ220 chassis #50, [Tom] was unlucky enough to see the dreaded check engine light come on last year.

He was lucky enough to get his hands on an SPD-1039 interface, built to talk to the Zytek ECU that runs the car. He was painfully aware that these devices are now incredibly rare and hard to come by, even given the tiny limited market of owners of 1990s Jaguar supercars. An initial effort to open up and reverse engineer the Zytek interface failed, mostly because it had been potted rather successfully in silicone.

He hooked up a logic analyser between the interface and the car, recording the traffic between the two.