einnod17

Just failed emissions test due to fault codes. The first is P0388 Camshaft Position Sensor B Circuit High Input, and the second is Warm up catalyst eff below threshold bank 2.

MIL light is on, couple time is started blinking and back firing but went away. I just ordered a new cam position sensor. First question: How do I replace it? I search on here but didnt find anything.

Second, is the sensor causing the backfiring and mil light or is something else wrong. I can definately tell there is a shortage of power, almost like one of more of the cyinders isnt even firing. Cant tell that much on the highway but at a light you can. Also, the rpms started bouncing when at idle, hasnt stalled yet but wouldnt be suprised if it did. Seems to take a little longer to start occasionlly as well.

Some one please help! Registration expires friday and I dont want to pay the dealer.

Car is 02' A4 3.0.

einnod17

So I found it. It looks like there may be two sensors. Is that possible? I replaced one, under the coolant resevoir, but it looked liked there was another one next to it. Any ideas?

tobin

But I had a CPS code a while back. Turned out that one of the sensors was just unplugged, but anyway...There is a sensor on each bank. One is on the left bank under the coolant resevoir, the other is on the right bank by the radiator. To replace them, unplug the sensor, unbolt the (two or three?) bolts on the sensor, pull off, and install new one. Sorry can't help with the cat issue. This is on a 2.8 but probably similar to a 3.0.