I recently bought a 1992 Buick Park Avenue Ultra (Series I L67) and it just threw a code 41 (cam sensor circuit). I'm planning on replacing the camshaft position sensor, as I believe this is the issue and it'* apparently somewhat common on Series I 3800s. The car idles decently but has a bit of a surge (usually surging from 800-1000 RPM at idle) and occasionally hesitates for a moment when accelerating from low RPMs. Is a bad camshaft position sensor likely to cause these issues? The car seems to run fine at the mid-high end. Also, any tips or ideas are welcome.

One of the most common causes for a non-working Camshaft Position Sensor on the 3.8L GM engine is the Camshaft Position Sensor Interrupter falling off from the Camshaft Gear. This is just a magnet held in place on the Cam Gear with a plastic holder. This plastic holder eventually breaks and the magnet button falls off.

1. Remove the Camshaft Position Sensor from the engine’* Timing Chain Cover.
2. Since you can not look directly into the cavity (left open by the Camshaft Position Sensor on the Timing Cover) to see if the Interrupter Button is missing or not... you’ll need to use a small hand held mirror to do it.
3. While a helper slowly turns the Crankshaft Pulley watch the Cam Gear thru the CMP Sensor Hole (using the mirror) to see if the Interrupter is there or not. It may take about two revolutions of the Crank Gear to see the Interrupter or the empty cavity on the Cam Gear where the Cam Interrupter goes.

Awesome, thanks. Sounds like fun...I'll be attempting it this weekend, wish me luck!

Late update! Cam interrupter magnet successfully replaced last Saturday. I'll be doing a little writeup on the method we used, probably this weekend.

Did it fix the problem?

Yep! CEL is no longer on and the car runs great. We used an alternate method of installing the cam interrupter that does not require removal of the timing chain cover. I can now confirm this method definitely works.

I would be interested in seeing a write up on how you changed it. I'm glad you didn't spend the money and time changing the camshaft position sensor, only to find out that was not the problem. Nice work.

There is a documented write up here:
Code 41: lost cam magnet in 3800

With directions here also (do not post to this thread, it'* freaking old, and you will get banned, I will make sure of it):
https://www.gmforum.com/1987-1991-93...emself-190434/

Lmao!! ^^^

Hey would you be able to send me your thread when you changed your cam magnet? Thank you Mike