Moinsen, it asks me a question: What is the purpose and purpose of the secondary air supply available in some Volvos? I don’t see it yet… Second question in the context: does a return to “without secondary air” result in a deterioration in any way? Is the sec-air captured and regulated by the engine STG? Background: on my AWD is a hose of this control (from the “valve” to the downpipe, directly behind the turbocharger to pump” completely porous and hardened, therefore broken. The new part arrived yesterday. A soft, supple hose. Logically, this, because hot exhaust air will be transported again in the future hard and porous. Therefore, I am looking to expand the entire stuff or upgrade to the exhaust preheating “before Bj 96″… But only if this does not cause any disadvantage. Unfortunately, have my laptop in the workshop and can therefore not be fitted to’s Vadis… Markus