Hi. My cat/exhaust warning light has come up permanently on my golf 04 tdi. Diagnostics garage said couldnt check ECM as codes P18000 map implausable and requires 16621 turbo booster sensor and 16497 intake air temp is high. Says needs new map sensor and wiring to sensor has no return voltage.

If this is ordered, does it go on my ECM, and then can it be read to find out what the problem is with cat/exhaust?

Any ideas?

Thanks, Bec