F40 lifting suspension computer problem?

I suspect that my F40 suspension computer has developed a fault. Has anyone any suggestions to avoid purchasing a new one. Can the computers be tested and repaired.

I will explain the problem and what I have checked, in case someone has other ideas.

While driving, the orange suspension error light came on. Afterwards, every time ignition is turned on, the suspension light flashes as usual. As soon as the engine is turned on, the orange light remains on signalling an error. I concluded that the computer does not store this particular error in memory when the power is off.

Connecting a Digitek D21 tester borrowed from another owner, gives the readings from front and rear potentiometers, but nothing else. Can not raise or lower suspension, or read error codes. I borrowed the same tester about 8 years previously to set up suspension heights, and it worked just as in the instruction manual.

I have verified that the 2 suspension raising valves and 2 lowering valves work by checking resistance and then hot wiring them. Similarly, hot wiring the pump motor or relay shows they work. I am able to raise and lower the suspension by manually connecting +ve current and -ve earth to the appropriate valves and pump motor. Also I can read resistance from the front and back potentiometers.

I have then verified the wiring is intact from the computer plug to each component.

The only other 2 inputs that I know of are the engine RPM, and the car speed. The first must be working I assume, because the system senses when the engine is turned on. I don't believe that an absence of car speed input would activate the system warning light,
but the light would just keep flashing as if 30 km was never reached.

So it seems to me, that it must be a computer fault. I have looked at the circuit boards, and I can not see anything disconnected or a cold solder.

Has anyone any further suggestions? Does anyone else with knowledge of the system agree with my conclusion?

 

After 8 years of F40 ownership, generally the system is fairly robust and reliable. The only recurrent issue is after not using the car for a long time, the suspension depressurizes completely causing the computer to log a fault and not work at next start up. There is a well documented fix for this, which has been posted elsewhere.

The lifting suspension is very good for awkward driveways, speed humps, and deep drains.

The high speed low setting is lower than the fixed suspension, and this is probably a bonus for track days.