Hello everyone, I have a Bentley manual and also a vag com cable with vcds. I can't figure out some of these codes...

To start off my car is:
1999 Audi A4 b5 1.8t (AEB) Quattro, Auto Trans with Tip Tronic.
150k.

Address 02: Auto Trans

2 Faults Found:
00296 - Kick-Down Switch (F8)
29-10 - Short to Ground - Intermittent
00526 - Brake Light Switch-F
27-00 - Implausible Signal


Address 08: Auto HVAC

2 Faults Found:
00779 - Outside Air Temp Sensor (G17)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent

Address 01: Engine

2 Faults Found:
16806 - Main Catalyst; Bank 1: Efficiency Below Threshold
P0422 - 35-00 - -
17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 35-10 - - - Intermittent
Readiness: 0000 0101


I have just replaced, All brand new coils, bosch oem plugs, Ignition control module, Tran's fluid and filter, Differential Fluid, Pressure regulator Valve, Downpipe and Flex pipe, Exhaust gasket's. I do have a 3inch test pipe installed, im sure that is causing the 16806 code under engine codes. Is the fuel trim caused by a bad MAF? Most of all any help on the tran's codes..? Or the Ignition timing off in HVAC.


Thanks everyone! Let me know anything that might help.