map sensor scaling/readings

hi, ive got a bosch 4 bar map sensor fitted to my car and the dta ecu has a preset option for this particular sensor

when the engine is off I'm reading about 102/103 kpa which id say is correct, however when the engine is started the engine hunting and I'm getting a reading of 102/103 kpa again

ecu isn't seeing any negative vacuum, however I have a standalone 4wd controller which uses a vacuum feed direct from the engine and its reading -35 to -20 kpa on idle whilst engines hunting

does this suggest incorrect wiring?

the bosch part number is 0281 002 316 and its a 400kpa sensor, can anyone confirm the pin out for this sensor and/or sensor scaling

Can you key on, engine off and test the sensor with a hand vacuum pump? This only works if it uses a hose to measure pressure.