Hi, I have a problem with the electronic A/C & Heater control unit on my 348 1990. Whenever I turn on "RISC" or "A/C" it displays the temperature setting for two seconds, and then displays "E8". It displays E8 until I turn the ignition off. If I do not use RISC og A/C, the unit seems to be working fine. When in RISC and E8 the unit heater works well. It seems to recall the temperature setting that I can change for two seconds during startup. I can also reduce the coupe temperature by alternating between RISC and "external air mode" (bottom left button). I live in Oslo, Norway, and the climate is not that hot, so most days in the driving season the outside temperature is below 20 C, and this is when the problem occurs. But on sunny days in June and July, when the temperature is above 20 C, the ECU actually works! Which is good for me, because this is when I need the A/C most One time I drove off on a sunny warm day, with the A/C working. After 30 minutes it started raining and the outside temperature dropped noticeably. And then, during driving, the ECU suddenly switched to E8 mode, without me doing anuthing. E8 concerns the "electric water pump for heating", and we while debugging the problem we have tried to connect to another water pump, but with the same result. We have also swapped the electronic A/C & Heater control unit with one from another car, with the same result. Does anybody have an idea of this E8-problem, which seems to vary with the outside temperature?
The problem could be with the external temperature sensor. It might be partially faulty, sending an out of range signal when exposed to lower temperatures.
I get an E1 code related to the in car temp sensor. Taping the screen to the left of the steering wheel clears it most of the time. This tells me there is a short in the system. This is what I would look for in your car. A problem with grounding or a connector. The cars are old, the electrical connections are old, stuff breaks down. I would start at the A/C-heater control unit behind the center console and work outward from there.
m.stojanovic, thanks for answering. It seems that the older 348s, including mine, does not come with this external temperature sensor. We have checked agaist a newer model, where we found one, but not on mine, unfortenately. It could have been similar errors in the other three sensors, but we have changed them, without any improvement.
