I`m the owner of Volvo 960, B204FT engine. I have a problem, and I dont know where to start looking for solution.
Occasionally it happen, that car have low boost, and my AC compressor go off. I also noticed, that when this is the case, my cooling vent is ON, and my idle is high (about 1100RPM) I check blink code, but there is nothing.
By looking wiring diagram, AC compressor, and boost valve are controlled by TCU unit.
I drive 1991 Volvo 940 with LPG (existing in the car since new). It reads on the "pump" (is it called the LPG pump?) "specially made for Volvo by Vialle". The system has been modified as I think there are remnants (electronics with some relays) that did not have any use now, cut wires in the engine compartment, then some very strange system for providing good idling rpm on LPG, etc. But the car run PeRfEcT on LPG - literally perfect, making it 8-9 EUR / 100 km in town, for years.