Need Help 2.4L Engine Camshaft Sensor

Jkb242

Silver Supporter
I have this engine in my 2013 Equinox which is identical to the current engine in the Terrain. Does replacement of the Camshaft position sensor require a relearn procedure. I was getting “camshaft bank 1 sensor B” low. Given that this a Hall effect device, it made sense that after 85k miles it likely was producing a weak signal. I replaced it with the exact AC Delco part and I’m still getting the code after resetting it following replacement. Possibly a relearn is required. Looking for input.

Thanks!!
 

gmcman

Well-Known Member
I'm assuming it does, but does the engine run? If so, sluggish, normal, hard starts?

Generally the hall-effect sensor should remain healthy unless the wire breaks.

Does it make a rattle or any odd noises from the timing chain cover? I believe these had chain tensioner issues and the chain could be loose causing a correlation issue.

I would also check the electrical connection for contamination, loose or broken wire along the sensor path, but possibly a tensioner issue
 
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Jkb242

Silver Supporter
Thanks for the input guys. The “low” signal report of the P2090, was what I was following to resolve this issue, which was my reasoning for presuming a faulty sensor given the mileage, now I see that the part replacement was not the correct procedure. Did not attempt tracing from sensor back to ECM given harness is free from nicks to ECM and in excellent condition. Haven’t pulled wiring diagram would love to have one but need to do a search to find. If there is one on this forum, can you please point me to it? Then I might discover that the three wires on the sensor do not connect directly to the ECM, to search for the “low” reported in the code. Would this signal be relative to the 5.0vdc reference or is it relative to the 12.0vdc rail?

It runs perfectly normal, idle is smooth given the dirty throttle body which I need to clean. Oil is full and color looks normal for 3k mikes since change.

So I assume no relearn is required.

Months ago it seem to rattle a bit after start but would sound normal or so I believe but may have simply gotten use to this less pronounced rattle accepting it as normal. Would a start up audio clip be of use in having “trained ears” have a go to see if what I think is normal really not? Happy to get this clip and post.

I became aware of the chain tensioner issues for this engine, after attempting some further study into possible issues and the fact I also noticed the P0017 code late yesterday.

Much thanks again and appreciate any additional input.
 

TJBaker57

Well-Known Member
there is one on this forum, can you please point me to it?

Have a close look at Moosemans signature at he bottom of his posts. (Can't be seen on mobile devices I think) There is a link to service manuals for download.

Edit: I see the link if I turn my phone sidewards.
 

Mooseman

Moderator
Unfortunately I don't have manuals for the 'Nox.
 

gmcman

Well-Known Member
Months ago it seem to rattle a bit after start but would sound normal or so I believe but may have simply gotten use to this less pronounced rattle accepting it as normal.
This could very well be your problem. The term "low circuit" IMO could be misleading. If your timing chain is stretched or the tensioner is worn/bad, this would cause an error in what the PCM is comparing the crank angle and the cam position to. Once it goes outside that parameter it will throw a code.

Now the question is, does your trouble code point to just the circuit or the overall cam/crank correlation or just the cam position, that I don't know.

Is the cover easily removable? This could answer our questions if the chain is loose.

Would a start up audio clip be of use in having “trained ears” have a go to see if what I think is normal really not? Happy to get this clip and post.
Sure, cold and hot would be great.
 

m.mcmillen

Gold Supporter
Diagnostic procedure from the service manual for both codes. If you have a P0017 it is pretty likely your chain is stretched or you have a broken guide. Pull the valve cover off and you can see the chain and the guides. The guide on the front of the engine usually breaks.
 

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Jkb242

Silver Supporter
Diagnostic procedure from the service manual for both codes. If you have a P0017 it is pretty likely your chain is stretched or you have a broken guide. Pull the valve cover off and you can see the chain and the guides. The guide on the front of the engine usually breaks.
Thanks a million for this input. The troubleshooting steps make perfect sense.

Initially, I should never suspected the position sensor, I completely missed the work actuator
in the P2090 code which screams the solenoid not the sensor.
I have performed all component test of the solenoid and all of the circuit tests I am able to perform. Since I don't have a bidirectional scanner, I cannot command the sensor on as described. I could use my scope to determine if there a PWM signal present but without full control of the solenoid, I cannot complete that part of the testing. The wiring diagrams I have do not show which of the three harness connection to the ECM contain the solenoid control, J1, J2, or J3 needs to be removed to make a continuity measurement to the solenoid. If you have a diagram that shows this it would be very helpful.
As far as inspecting the chain droop or slack, I'm not sure I am up for removing the intake to do this. I don't have anything showing the removal procedure.

Thanks
 
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m.mcmillen

Gold Supporter
I didn't read the diagnostic procedures in much detail. Let me know what wiring diagrams you need and I'll get them for you. As a starting point, I'd clear out all the codes and run it until the check engine light comes back on and diagnose whatever code comes up first.
 
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Jkb242

Silver Supporter
Thanks again, I would love to have the wiring diagram showing the connection from the ECM to the Camshaft actuators. It appears that there are three high capacity connectors to the ECM. K20 mentioned in the circuit troubleshooting guide is the ECM I don't know which one should be removed or if they all are coupled together and all are removed together. So for the harness continuity or short test, I need to know which pin on the ECM is the one that requires backprobing.

Much thanks if you have this.
 
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Jkb242

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I have located a couple of wiring diagrams tht seems to add more operational information as to the nature of the camshaft timing control managed by the ECM. This information is free by the way directly through your public library if you have a library card. Simple ugh? But you need to search for Auto Repair Source to get this particular set of information. The Chilton library is also there as well which in my case was the default auto repair data returned. Anyway, I learned something in this search regarding the Camshaft sensor and the acutator or solenoid. Its the Hall Effect cam sensor to which the 5V reference bias that provides the sensor information to the ECM, to control the PWM signal that is required to operate the cam actuator for the proper duty cycle of the solenoid timing to make the adjustment. For me, the troubleshooting now seems a bit more logical. Hope you find this interesting. Much thanks
 

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Jkb242

Silver Supporter
I didn't read the diagnostic procedures in much detail. Let me know what wiring diagrams you need and I'll get them for you. As a starting point, I'd clear out all the codes and run it until the check engine light comes back on and diagnose whatever code comes up first.
Good idea to clear the stage and see where we are...
 
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Jkb242

Silver Supporter
I think it’s time to mark this thread above solved if possible BUT not replies 11,12,13. The reason is that the remainder of the other are of no value to anyone, given what was discoved.

I would like to post an audio clip of the Engine at idle. Additionally, I did discover that without the air box installed which connects the airflow (MAF sensor to throttle body, the engine would start then run very briefly then die. This was unexpected since I had the vacuum line from the intake manifold intake blocked off. I thought it would run at least idle and possibly throw codes but not even idle.

Replacing the air box it runs and idles normally. Will follow up after test drive today regarding Camshaft actuator codes following exhaust connector and actuator cleaning. Thanks
 
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Jkb242

Silver Supporter
LATEST UPDATE ON THIS THREAD

After cleaning the exhaust cam actuator connectors and the connectors on the actuator P2090 is no longer reported by the ECM. The code I have now is P0017. I have never removed the intake to access the cam chain nor do I have a bidirectional scanner. I only have hand tools and my 2 car garage in which to work. I would so appreciate input on the repair process and if this is something that is pretty straightforward. Again car runs fine, if I did not have a CEL, I would have no idea there was anything abnormal Thanks!!
 

m.mcmillen

Gold Supporter
They are not incredibly difficult. You just have to be 100% sure you have all the timing marks where they should be. I would also recommend changing the water pump at the same time since it runs off the timing chain.

You shouldn’t need to take the intake off. Maybe what you’re thinking about is the big air box on top. You should just have to remove the valve cover and the timing cover.

I’ve done a few of these chains. I can get you service info for that, also.
 

m.mcmillen

Gold Supporter
These are the instructions for the chain. They list some special tools. The only thing you really need is the angle gauge. The holding tool, you can just use a wrench and hold the camshaft.
 

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Jkb242

Silver Supporter
They are not incredibly difficult. You just have to be 100% sure you have all the timing marks where they should be. I would also recommend changing the water pump at the same time since it runs off the timing chain.

You shouldn’t need to take the intake off. Maybe what you’re thinking about is the big air box on top. You should just have to remove the valve cover and the timing cover.

I’ve done a few of these chains. I can get you service info for that, also.
That would be great and very much appreciated. I’m not certain exactly what I’m looking for except a n obviously loose chain. Looks like a bear having to go down around the crank where there are also marks that have be aligned with those on the intake and exhaust cams. This I picked up from just watching YouTube videos. What does that GM kit cost to do this complete procedure if have purchased them in the past? Thanks so much!
 

m.mcmillen

Gold Supporter
I posted the instructions just above your last post.

Don't be intimidated by the marks. In some ways a chain is easier than a belt. The chain has marks on it and as long as you have the marks on the chain and the cams and crank, you're good to go.

A loose chain is what you're looking for. You need to change the chains (timing and balance shaft), tensioners, guides, and sprockets. Rockauto is a good place to get them. Cloyes in an OEM supplier to GM so that brand is the one that I use.

I don't have a lot of pictures from when I did the last one but you can see in the first one that the chain is not tight in between the cams. The second picture shows it tight with the new parts. Also notice the difference in the sprockets on the crankshaft. It was really worn down. This one also had a broken guide but I couldn't find a picture of that.

Screen Shot 2020-07-27 at 9.03.02 PM.png
Screen Shot 2020-07-27 at 7.38.26 PM.png
IMG_5176 2 copy.jpg
 

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Jkb242

Silver Supporter
These are the instructions for the chain. They list some special tools. The only thing you really need is the angle gauge. The holding tool, you can just use a wrench and hold the camshaft.
This is great I do appreciate your input and the encouragement!! Since it is running fine is it safe to assume it’s in time? Not ignore the issue just to make it unnecessary to rotate either cams or the crank since any VVT that’s needed will then be possible by the ECM. I saw one video where the timing marked on the CAM AND CRANK had to be moved then the chain could be installed. It seems that if the engine is currently in time NO rotation of CAMS OR CRANK should be necessary. Would that be an accurate presumption? Thanks so very much!
 
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Jkb242

Silver Supporter
These are the instructions for the chain. They list some special tools. The only thing you really need is the angle gauge. The holding tool, you can just use a wrench and hold the camshaft.
Thanks!
 
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m.mcmillen

Gold Supporter
The procedure in the manual tells you to put number one piston at top dead center. This gets them pretty close. I usually have to turn the cams and crank to get everything to line up properly. It isn't much usually, just a few degrees. Also, I find it is easier to remove all of the spark plugs so you're not fighting the compression in the engine when you're turning it over by hand.
 
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Jkb242

Silver Supporter
Today, I took a really close look at the engine position and the potential items of interference that might prevent complete access in preforming replacement of the chain and tension components. The engine mount is directly in front of the lower engine compartment where the chain attaches to the crank and water pump. Have you encountered this and how were you able to work around the mount? I wanted to get your input and if removal of the engine mount or bracket is recommended to get free access to the engine. It seems that if I have to remove the mount, the engine might shift downward on that side making it necessary to support the engine from the floor of the garage. I want to be well prepared before starting this to insure I can correctly perform the procedure.

Thanks.
 
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Jkb242

Silver Supporter
I would happy to post pictures of this issue if it would help.
 

m.mcmillen

Gold Supporter
The mount doesn't interfere with anything. The timing cover is just below it. You have to fish the chain down through the top since the timing cover does not cover the entire front of the engine like it does on many engines.

edit: I attached a photo that shows most of the size of the opening with the cover off. You can see just above the opening the engine mount. IMG_8246 copy.jpg
 
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Jkb242

Silver Supporter
The mount doesn't interfere with anything. The timing cover is just below it. You have to fish the chain down through the top since the timing cover does not cover the entire front of the engine like it does on many engines.

edit: I attached a photo that shows most of the size of the opening with the cover off. You can see just above the opening the engine mount. View attachment 95863
I had not seen your reply before sending the picture clarifying my concern of the engine mount. Your picture is very helpful in detailing a correct install. Nice. Unfortunately, I am unable to see the same view of this detail since I would be working from above the engine looking down. It also seems the engine bracket would prevent removing the timing cover unless it is removed, but that would mean disengaging it from the engine mount. I have not removed the front tire to check for clearence and for working from that point since focusing my attention entirely on the instruction guide you provided.

Thanks
 
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Jkb242

Silver Supporter
Your picture made something clear to me that I had not previously noticed. There are two chains inside the timing chain cover riding on different sprockets of the crankshaft. Certainly obvious and likely why you were wondering why I was concerned about the other tensioners inside the engine timing cover. Sorry for being so myoptic! It's pretty obvious from that picture.

This helps me understand your comments a little more clearly and greatly simplifies the camshaft timing chain service required. The camshaft chain directly contacts the front crankshaft sprocket simply looping back to the intake and exhaust main sprockets. The only component that requires replacement behind the engine timing chain cover is the one tensioner for the camshaft chain which appears to require removal of the front tire for access through the wheel well. Does this access allow full exposure to the tensioner for repacement?
 

m.mcmillen

Gold Supporter
Don't cut corners and replace only what might be bad. I replace everything under the cover. Chains, guides, tensioners, and sprockets. You also have to replace the VVT sprocket bolts they are torque to yield.

This is the part number for timing kit 94201SAVVT1

This is the part number for the balance shaft kit 94202S

Between these two kits, that will be everything you need except the water pump. Rockauto is a good source for these parts but sometimes Amazon has them, too. You can actually change the water pump on these without removing the chain. There is an access cover that comes off of the timing cover and there is a tool that you can use to hold the sprocket in place so the chain doesn't come off.

But, before you go and buy parts, I still suggest you take the valve cover off and see if you notice the chain having any slack in it or a broken guide.
 
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Jkb242

Silver Supporter
Very sound suggestions. In all the threads I missed the point to check for slack first. I guess I was thinking that given the only code remaining P0016, and this issue being such a common curse, there wasn’t much else it could be, especially with it running so well, but just outside the correctable limits. This inspection recommendation seems a good last check before taking the dive. Thanks
 

m.mcmillen

Gold Supporter
It is highly likely it needs chains. I just like to be sure when I’m getting ready to spend a lot of money on something.

The last one I did I was in a hurry and bought the parts at the dealer. They didn’t have any kits in stock but there was a shipment of 6 kits coming the next day. If they keep that many in stock you know it is a problem.
 
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Jkb242

Silver Supporter
Oh brother, this has become a saga. I decided not to do the repair myself, no lift and just a wee bit beyond what felt confident doing, having no actual experience with this repair. I took it to my backup mechanic, honest and trustworthy, but not inexpensive either, but ain’t that about par for the course too?

His quote based inspection of the work required, is $1550 for the 9-4201vvt kit installed. He hasn’t started on it yet as we just arrived at the quote yesterday but today, the rethinking begins. I have requested he hold up pending further discussion of the specifics of his diagnosis to confirm what I reported as a likely tension issue. Back to the code P2090, I tell you my friend, if one can believe in the code description, the words “circuit low” bothers me. Further regurgitation and thoughts, in addition to the repair cost, is diverting my attention to what diagnosis was performed concerning the fricking circuit? Was the cam position sensor signal probed for amplitude and waveform was continuity confirmed between the position sensor and the ECM? I didn’t do this, and now I think I should have. I don’t have a bidirectional scanner but I have a scope and I know how to use it. Did I simply presume something I should not have? Having to ask that question now is my fault, without a doubt, but if my mechanic didn’t confirm this, it’s time to do it now, before a wrench is turned. I agreed to proceed with the repair based on what? Your input has been invaluable and in no manner would I attempt to second guess it. I think you would agree that with this code, presumptions I made by not confirming a possible defective replacement sensor or a possible electrical issue (circuit low) between the sensor and ECM, must be eliminated. Perhaps the mechanic didn’t either. So that’s what I will need to confirm Monday before proceeding. My mechanic is no special wonder, he has to exercise the same steps as everyone else and considering he hasn’t ever done this repair on a VVT, we both need additional confirmation before proceeding.

I will ask your confirmation on one point if you haven’t already decided I’m crazy, I believe the cam position sensor is biased by the 5v supply which the ECM can track as the sensor output becomes superimposed on the 5v bias. Assuming this to be correct, if there is a true circuit issue as reported by the DTC, it has to be confined to the sensor/ECM connection nothing else. Can you confirm? The very last thing I want is a huge repair bill and the code is still there. That’s going to be painful for me and the mechanic! I don’t want to go there ever!

I’ll keep you posted.

Thanks a million
 

MRRSM

Lifetime VIP Supporter
If you can do this without seeming to insult your Mechanic... Try to work it into the conversation (...in a non-pejorative manner) and BEFORE you cast your final agreement in stone for him to do this work... that he WILL return ALL Broken Hardware to YOU.

These items should include ALL Used Chains, All Used Removable-Replaceable Sprockets, ALL Used Timing Chain Tensioners and ALL Used, Broken or Damaged Timing Chain Guides so that you can take some decent Post-Evaluation Images to bring back and share with us all here.

Any Future and Past owners of this Vehicle beset with this problem... WILL Bless You for this Effort. TIA :>)
 

m.mcmillen

Gold Supporter
Have you changed the VVT actuator valve? The exhaust one in your case. They're common to go bad and it is best to go OEM on these. I would think this would be the likely cause of the P2090.
 
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Jkb242

Silver Supporter
I did not replace it but cleaned it thoroughly and performed all resistance measures that are recommended on the device, and confirmed plunger action using a 12v source, Replacing it will be my next step which I had intended to do before taking to the shop but it dropped of the radar when I decided to take it in. Not exactly a brilliant move when it should have been the FIRST thing after making sure the harness feeds to it were ok.
 
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Jkb242

Silver Supporter
Update to original issue— Requesting comments and input

I decided to turn this issue to my go to mechanic who is good and completely trustworthy. It became obvious that the repair needed was likely headed toward a chain and guide replacement kit, just a bit beyond my comfort zone. My mechanic encountered nothing I have read about or discussed here concerning VVT engines that appears to the actual cause of the exhaust Cam timing beyond correction.

What he found was the magnet mounted on the position sensor end of the exhaust camshaft had apparently shifted position to the extent that was preventing timing correction from the exhaust valve actuator to correct. He discovered this after locating a SB on this engine then proceeded to replace the camshaft after he had completely rechecked the chain and tensioner positions. Recall the engine was running with no issues and no OBD codes and otherwise performing normally, other than the exhaust cam timing mentioned previously. After the chain guides and tensioner were replaced the VVT time was still out of spec. After replacement of the camshaft, the code was not presented again after several test drives. It appears that this has corrected this issue. What I would like to know is that given nothing like this has been mentioned here or anywhere else regarding the common VVT timing issues, has anyone ever encountered this camshaft defect? If not, I am surprised and if after the final additional drive test next week, since my mechanic still has the vehicle, this discovery might be of interest to others.

Thanks in advance as I look forward to input from the wonderfully talented resources of this forum.
 

m.mcmillen

Gold Supporter
I have heard of that service bulletin but have never experienced the issue. Glad that it seems to be back up and running now.
 

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