BMW Repair: passenger seat stuck in decline position & codes P1421 & P0133, mechanical linkage, o2 sensors

Question
VIN #AV40305 328i 1996 BMW passenger seat is stuck in decline position. The motor runs but the seat will not move into the upright postion. Another problem is two codes P1421 & P0133

Answer
Vernon, as far as the seat goes, you'll need to access the four bolts or nuts that anchor the seat rails to the floor and tilt the seat back to look underneath and see mechanically what is going on under there. One bolt or nut at the end of each seat rail. I don't remember if the seat backrest (which I take to mean what you are talking about) is cable drive off of a motor to a gearbox or a motor and shaft to mechanical linkage. The Pcodes are as follows P0133 is BMW code 229 for O2 sensor circuit slow response (bank 1 sensor 1). and P1421 is Secondary Air System (bank 2). I would troubleshoot the O2 sensors first as the O2 sensor may not be picking up the Extra air being injected by the Secondary air pump on start up. But be careful the faults could have been set the other way as a Low or no Secondary air output will cause a O2 fault because the Oxygen sensor isn't seeing an increase in oxygen level from the Secondary air system. Usually this causes a mixture fault though. I would remove the pipe from the Secondary air pump to the One way valve and either manually power up the Air pump by jumping the relay or give the car a cold start. You should feel a strong flow or air through the hose. If you don't you know your problem is with the Pump, wiring, relay or signal from the Engine computer. If Airflow is good then these components are okay and start looking at the oneway valve, vacuum supply to the valve or the O2 sensors. Reconnect the air hose to the oneway valve and apply vacuum to the oneway valves vacuum port (remove vacuum line), remove the O2 sensor from the exhaust manifold and activate the Air pump again. Can you feel a similar amount of air out the O2 sensor port? If this test is good then you should replace the O2 sensor or recheck the vacuum supply to the Oneway valve on cold start. O2 sensor are to be replaced at 100,000 mile intervals.
-Evan