Golf Mk2 1.8T AUM Only getting 5psi of boost. I believe this is soft limp mode. It doesn’t fluctuate, just at a solid 5psi. N75 valve wiring shows 13.2v and the valve shows 27ohms of resistance which I believe is within tolerance. Tried a mates N75 and still only 5psi. If I remove the actuator pipe from the valve I get upto 20psi. I removed actuator and pressure tested, moves freely. If I remove MAF sensor plug the idle drops a little. I want to try and figure this out and not just buy parts until it solves it. Best option I assume would be to use VAGCOM and run some tests. Anyone got any ideas? Fault codes I have – 18057 – ABS 18058 – Instrument cluster 17931 – Airbag 17834 – N80 valve 17522 – Lambda 2 resistance to high 17526 – Lambda 2 open circuit 17840 – Secondary air valve N122 17841 – Secondary air pump J299 relay I have no ABS, airbag, N80, N122 or J299. And I have 1 lambda (no cat). Cheers for any input
All of those can be coded out by an ecu specialist try @Toyotec on here aka Adlai Phillips on FB, also try Chris Bellman or James E Looms. in vagcom you can start to flick thru the ecu measuring blocks, this will show all your sensor inputs in real time. maf grams/second, boost requested and actual, inlet and coolant temps, throttle and pedal position worthwhile place to start
