Originally Posted by dawson1112
I don't trust dealer mechanics! Period. They're answer to every thing is "we think ".
If you want to know for sure , take the alt off and have it tested. The dealer mechanic will just continue to guess and unfortunately all at your expense. And here is how the scam works,,,
We replaced X sensor because it was bad... 150 buck. ( problem not solved )
Well driving the car with that sensor bad caused this part Y to go bad.. 150 bucks
( problem not solved )
Since that part X and Y were bad and your continued to drive the car it caused part Z to go bad and now the whos is whats it part is bad...another 300 bucks. Rinse and Repeat!
They always assume that you have no clue. So, they continue to guess all while making you feel like its your fault and they are genius.
Cam sensor wiring routed too close to spark plug wiring (causing interference)
Poor wiring connection at cam sensor
Poor wiring connection at PCM
Bad cam sensor
Damaged reluctor wheel
A good mechanic ( who is not inclined to rip you off ) would start doing visual inspections of the wiring and components including the reluctor wheel that the cam sensor reads off of.
Did they give you a specific code ? There may be more than one code for a cam shaft sensor.
Having a good relationship with the dealer avoids you getting stuck with the bill if they replace a part that doesn't fix the problem. Dealer I work with has always been straightforward with me. Never got stuck paying for something that didn't fix a problem I came in with that I couldn't/didn't want to fix myself.
I'm sure you've NEVER made a diagnostic mistake mr perfect.
Anyways, OP, it IS most likely the alternator. It's know problem on S197 models that a failing alternator causes that code to be thrown. It has to do with a feedback loop or interference in the electrical output of the alternator that causes the sensor to be misread by the PCM.
What I don't recall is if bench testing will necessarily show the alternator is failing, especially since most of the testers only check for Volt/Amp, they don't check the quality or frequency of the voltage (oscilloscope).
btw, here is a TSB on it...