FAQ: P0341 Camshaft Position Sensor (Cam Sensor / Timing Chain)

Quote :

I WROTE YESTERDAY: Well, I can confirm that the infamous black wire exists in the 1995 Series 1 SC.  It is located in the lower left corner of the firewall harness block, and is black with white stripe.  It terminates in the camshaft position sensor connector's center pin.

However, it appears that my black wire is not broken.  I was able to run a continuity test and impedance test from the center pin of the camshaft position sensor connector to the "black wire" pin in the firewall harness block with no drops even with moving the harness/wire around extensively.  So unfortunately so far I am not finding that the wire is the problem.

But I'm still getting the P0341 DTC so that only leave a few options since I've already replaced the camshaft position sensor.

I'll have to check if the inductive magnet is still in place or not.

And I'll need to check the continuity of the wiring from the firewall to the PCM.  I may even swap out the PCM itself since I have a spare.

BTW, does anyone know what the other two wires in the camshaft position sensor do and where they run? There are three wires in the sensor connector. These two wires are on either side of the center "black wire" pin.

Just ignore what I wrote above.  I think I misidentified a black/white wire as the infamous "black wire" and so my testing is invalidated.  The black/white wire did trace via continuity to the cam sensor connector, but that may be ground versus signal.

After consulting my FSMs for the 1995 Riviera, I think I've got some more tracing to do.

I did swap out to my spare PCM, but the result was the same.  So the PCM doesn't seem to be at fault.

The FSM starts troubleshooting with pin RB9 on the PCM red harness which should read 5V with the key on, and all three (blue, white, red) PCM harnesses disconnected.  My pin RB9 is not reading 5V, so the broken black wire issue is still a possibility.

Unfortunately a huge thunderstorm blew in just as I figured this out, and now we're approaching sunset, so it doesn't look like I'll be doing any more troubleshooting today.

I'll update as I learn more.

Look in the FSM.

https://www.ebay.com/itm/95-1995-Oldsmobile-Aurora-and-Buick-Riviera-service-shop-manual-used-Two-volumes/152572239100?hash=item2386039cfc:g:ZvgAAOSwlndZMzbU&vxp=mtr

LARRY70GS wrote:

Look in the FSM.

https://www.ebay.com/itm/95-1995-Oldsmobile-Aurora-and-Buick-Riviera-service-shop-manual-used-Two-volumes/152572239100?hash=item2386039cfc:g:ZvgAAOSwlndZMzbU&vxp=mtr

Yeah, that's on my list to do today as well. I have the FSMs for the 1995, but thought I'd just ask.

My assumption is that the other two wires provide power and ground, but will see.

OK, thought I'd provide an update.  After driving the car for about a week with no issues, I think it is safe to say this problem is fixed.

So short story; it was the Ignition Control Module.  Replaced with a genuine AC Delco ICM, along with new AC Delco wires and coils, and new Autolite iridium plugs and the misses under hard acceleration and P0341 code is no longer being set.


I can confirm that the 1995 SC has the same often troublesome black wire in the lower left corner of the large firewall harness connector, but in my case it wasn't broken... yet.  So that wasn't my problem this time.  But I also can confirm that wire is under undue stress and is probably why it does break for many owners.  I don't think it is an issue of a bad batch of brittle or defective wire though, although that is certainly a possibility.  I think it is more likely that the wire's location relative to the harness loom and the connector put much of the stress and bending on that one wire when the engine moves.  Over time this breaks the wire.  I noticed that one black wire was a lot shorter and had a fair amount of tension on it as compared to the other wires in the bundle/connector.  Perhaps a good preventative measure would be to proactively extend the length of that wire.

In my case, we'd had ignition problems before and didn't have the time for DIY so took it to our local shop, which I think turned out to be a mistake.  They changed our ICM twice in the last few years (which should have been a clue since ICMs should last the life of the car), and I found two things that indicated they really didn't do the job right.  First, the ICM they used was a "store brand" ICM which probably wasn't the root cause, but I've read enough reviews of off-brand ICMs only lasting a few months to a year, that didn't build confidence.

And upon pulling the plugs, I found they were in terrible shape, and likely were the same copper plugs that I installed years ago.  You might say that is my fault, however I was fairly sure the shop had (or would have) checked the plugs, coils and wires when the ICMs failed previously.  Now I'm not so sure they did, and that's what probably killed the ICMs.  So, key (and perhaps obvious) point, check your plugs.

I had reached this point after tracing and testing all the relevant wires per the FSM.  All traced and tested good, so that indicated either a PCM or ICM issue.  I had a spare PCM, and trading that out didn't help.  So that left the ICM.

So, I just went ahead and refreshed the entire ignition set with a new ICM, new wires, and new coils. Genuine AC Delco wires are only about $40, and the AC Delco coils too are about $40 each.  Although the wires looked good, the coils were 23 years old, so thought it was cheap insurance to just replace it all. And the genuine AC Delco ICM was only a little more expensive than the off brand, so again, cheap insurance.

turtleman wrote:

GM specifies the bolt be tightened to 44in lb

Where did you get 44 in/lb from? I couldn't find a number in the FSM (although it could be buried in there somewhere). Here's a thread on fullthrottlev6.com that gives a couple different numbers - link FlyingGTP says 48 in/lbs and BlazinRedGTP says 89 in/lbs(!) for the camshaft position sensor bolt and 22 ft/lbs for the Crankshaft Position Stud. I didn't see a stud, WTF?

JR,
Are you replacing your cam position sensor also.???

Yes, I replaced the cam positiion sensor. The old one was o.k., but the way parts are layered on top of parts on top of parts on modern cars, I figured I might as well replace the sensor while I was in there. I'm also debating replacing the harmonic balancer when I do the crankshaft position sensor. The harmonic balancer is expensive, but the rubber on the old one is old, and I don't know if I want to replace the balancer more than once.

I changed my crank position sensor as the one in my car was showing signs of failure well before 100K miles. After it's replaced you need to do a crank re-learn procedure. At least that's what the manual calls for. I had a friend at the time that had a snap on diag tool that did most of the functions of a Tech II.
So i was able to do it for free.

I reused the harmonic balancer though. I guess I didn't see anything wrong with it. I can't remember.
One thing I do remember is that the bolt is Torque to Yield and should be replaced with a new one if you want to follow the book by the letter. I've seen some GM tech's just re-use them.
I bought a new one as I already was making an order for other OEM parts at the time.

Rickw wrote:

I changed my crank position sensor as the one in my car was showing signs of failure well before 100K miles. After it's replaced you need to do a crank re-learn procedure. At least that's what the manual calls for. I had a friend at the time that had a snap on diag tool that did most of the functions of a Tech II.
So i was able to do it for free.

Wonderful, how about the camshaft position sensor?  

So I need to find a Tech II or similar to do the crank relearn procedure?  I watched a guy on YouTube do it with a $2000 tool.  Looked easy other than getting ahold of the tool.

Quote :

I reused the harmonic balancer though. I guess I didn't see anything wrong with it. I can't remember.

The rubber was younger then.  

Most likely I'll hold off on buying a new harmonic balancer if I don't see a problem with the one I have.

Sorry JR,
Didn't realize I forget to answer your question out the camshaft position sensor.
But I still have no answer. I never changed mine and don't know what the FSM says about that.

I'd look in my FSM but I already have the 3 volumes boxed and taped waiting for someone that may need them.

I'll wait a few more weeks and then I'll put them on Ebay and see what happens. My only problem with that is I now have a "Smart" phone - It's smarter than me and I don't know how to transfer picks from it to my computer to then load onto a site or forum. I think I need to buy a micro-SD card to do that, but I'm not sure.

Anyway, I think you already have the manuals so you can find out what the procedure is. If you don't have the manuals, let me know and I'll cut the box open to look or ship them to you for a small fee + shipping cost.
Rick

I've got the manuals, but the index doesn't have an entry for the camshaft position sensor. I'm sure the answer is buried somewhere in those thousands of pages. It could even be here in this thread. I guess I'll have to dig and see.

Jack the R wrote:

I've got the manuals, but the index doesn't have an entry for the camshaft position sensor.  I'm sure the answer is buried somewhere in those thousands of pages.  It could even be here in this thread.  I guess I'll have to dig and see.

I don't have my manuals in front of me, but IIRC the magnet on the cam passes the cam sensor 1x per revolution and the Crank is tricky. The reason the harmonic balancer tone wheel has an irregular tooth pattern is so that the crank's hall effect sensor can tell the PCM if it's in the first, second or third 120-degrees of the 360 degrees of its rotation.  The system is designed to be able to start the engine in only 120 degrees of rotation, which is why when everything is working right the 3800 series engines start so quickly with a flick of the key.

So basically the crank relearn helps the PCM learn the crank position.

IIRC the manual set refers to the crank relearn pretty much everywhere you remove/replace a part that is involved with base engine timing. You can find pointers to the crank relearn procedure in various places in the "Engine" volume.  Note:  They call it the "CASE Learn."

Also IIRC if you can start the car at all and tolerate goofy operation for a little while the PCM will CASE learn itself after you hit the correct rpm thresholds while driving for whatever reason.  See https://sep.yimg.com/ty/cdn/yhst-21854666697846/gm-crankshaft-relearn-instructions.pdf for context.  See our old post https://rivperformance.editboard.com/t9010-crank-sensor-relearn for even more context.  And see http://www.g6performance.com/forum/archive/index.php/t-4830.html for one person's manual procedure.  

If you have the Tech II it takes about 5 minutes to do a CASE relearn. Seriously. You might want to tak your car to a GM dealer for an oil change and let them do it for you while they are at it (just kidding)... or maybe for a 15 minute or 1/2 hour diagnostic charge (not so much kidding)...

And finally here is an anaswer that covers scan tool and manual re-learning for many functions on GM cars including the CASE Learn: https://ls1tech.com/forums/pcm-diagnostics-tuning/1596433-gm-computer-relearn-procedure.html

Albertj

Just finished reading through 10 pages of this thread, albertj posts the answer in the meantime.  Well hey, at least I learned about that dastardly black wire in the firewall harness.  I can't believe I've been driving around all these years with that sword hanging over me.  We're going to have to make a thread for this class of problem, so people don't have to read every thread on the forum to find out about the black wire or the plastic coolant elbows or the LIM gasket.

edit - none of those links say changing the camshaft sensor requires a CASE learn. If theren's no danger of damaging the motor, and I haven't seen any, I'll run it and see what happens.

It's definitely pointing to the need to buy tuning software though.

LARRY70GS wrote:

Did we ever find a source for these connectors?

Jack the R wrote:

LARRY70GS wrote:

Did we ever find a source for these connectors?

Contact this ebay seller & send him that picture

https://www.ebay.com/i/361295822482

the link points to a weatherpack kit on offer.