In this era, it was not uncommon to use two ECUs to manage a V8 or V12 engine. This was the case for the Ferrari Testarossa as well.

The issue wasn’t related to temperature, but from time to time, one bank of the engine (six cylinders) would cut out completely. After discovering that Ferrari used two Bosch Motronic ECUs to control the engine, I began to suspect a familiar problem—one I had previously encountered while servicing BMWs equipped with the same Motronic system.

Upon further investigation, measurements pointed to a dried-out electrolytic capacitor. Its capacitance had dropped below specification, and its equivalent series resistance (ESR) was significantly higher than normal.

This was the same fate that had befallen nearly every Motronic unit still in operation—at least, those that hadn’t already been damaged by water.