My 1998 A4 Avant 1.6 has just failed MOT. Not many issues, just a wee leak at Rear Brake Caliper, hopefully just needing pipe tightened or new se , Ratchet on Hand-brake just stopped working, and main issue CO2 Exhaust Emmisions following Fast Idle, it passed on natural idle. The mechanic not entirley sure what issue was.

I had had issue with the Mass Air Flow Meter, and had disconnected it as it had been running badly. *** this made such a difference I had actually forgotten to replace it. We did run emmisions test with it disconnected and connected and on both occasions it failed. The reading was 0.683 on both first and second Fast Idle tests.

Could it be the MAFM or could there be any other reason for the CO2 reading to be too high on fast idle? What is the logical course of action to get to the of this problem.

Also the Hand Brake ratchet was working fine just a week ago and now if I try to apply the hand brake it works perfectly but no ratchet to lock it on. I have never dismantle a handbrake and the Haines Manual does not really seem to mention the ratchet element of the handbrake. Has anyone got any ideas what the problem could be and how to remedy? Could the fluit leak at caliper have any link?

Many thanks,

Doug