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I have been having a recurring issue with my 2003 Honda Civic EX (AT): About 6 weeks ago when I was driving through the mountains in Western MD my car hiccuped and threw a P0341 code. I did a little research and found that the code is usually indicative of a CAM shaft sensor failing. I purchased an OEM replacement part and installed it about 4 weeks ago. I didn't have any issues after the replacement until.....I was driving back through the mountains this weekend and the car hiccuped again and threw the P0341 code again. The MIL turned off after a few restarts and the car ran fine for a few days until I drove home back through the mountains and the P0341 code reappeared for a third time. The other odd thing is that the alternator belt started squealing the same day the first time I got the P0341 code. I assumed it was unrelated and due to me using the a/c in the car for one of the first times this year (I changed the p/s and alternator belts this winter and I assumed I just didn't have enough tension on the belt), so I slightly increased the tension on the belt and solved that problem. Well.....after the second time I got the P0341 code the squealing belt came back. It only squeals for a second on start-up. Would something related to the P0341 code also cause the belt to start squealing? Is there something other than the camshaft/TDC sensor that can cause a P0341 code? Why does the car only throw this code when I am climbing in the mountains? I would think if there was an issue that the code would be thrown at intermittent times not always in the same conditions. Tomorrow (it is raining outside now) I plan to check the connector on the camshaft sensor to see if there is just a bad connection with the sensor.

One more piece of possibly pertinent information: The timing belt was replaced on the car about 60k miles ago.

Any thoughts or insights into this issue will be greatly appreciated. Thank you in advance.

 
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Loose female terminals in the connector?

Can you make the code set if you drive at higher RPM on flat ground? (Simulate the RPM and load of climbing up a mountain, or whatever it is you are doing in the mountains.)

The scenario you give makes yours a real head scratcher, if it's accurate. I can't think of any good reason why altitude would have any effect on something like this code.


I've heard of aftermarket belts causing misfire codes, I wonder if this might be a possibility in your situation....



Purchased from a Honda dealership, or was it "O.E.M." brand from a discount parts store?

 
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Thanks for the post!

I purchased an OEM part from a Honda dealership, Bernardi Honda.

I haven't had a chance to check the connector.....yet. I plan on doing that this evening.

The belts I used were purchased from Advance Auto and they are made by Bando who is the OE supplier. Do you think that could have something to do with it? I have another belt that I could swap out the current one if you think it would help in troubleshooting it.

Not sure I can simulate the load but I could drive on the highway around here in 3rd gear to simulate the RPMs. There really aren't any major hills/mountains around here. I don't think it is an altitude thing because the mountains aren't very high.....I think the highest is like 3k feet but it is a steep climb so the RPMs always are above 4.5k in order to maintain speed going up the hill.

 
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Pin drag test.


I seriously doubt it would change anything, but I have seen stranger things happen in the past.

I just threw it out as one of those oddball things from way out in left field.

Up to you.
I didn't really mean altitude as in having something to do with it, I was thinking load and RPM going up a mountain.

Try whatever you can, see if you can nail down some other pattern that makes the code come on.

Got freeze frame data from the code you can post? That would tell the RPM, load and speed, temperature, etc. when the code set.

 
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What is a pin drag test?

I probably will change the belt out, just to be safe. I will do that this weekend after I have had a chance to recreate the issue. I didn't have a chance to look at the connector today (I didn't get done with work until waaaay late).

How do I get the freeze frame data? I've been using the scan tool at the advance auto to pull the codes.

 
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http://www.jumperkits.com/how-to-per...ith-jumperkits


This came up in the google search too, but I didn't watch all of it.


The cheapest of cheap code readers don't have that function.

 
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Two things:
1) The pins on the connector are good.
2) I was able to recreate the issue by holding the RPMs just below 5k for about 10-15 seconds.

Any ideas on what could cause that? I am going to replace the belt this weekend to see if that fixes it. I am also going to see if I can get a scanner with freeze frame and recreate the problem then pull the info. I am open for any thoughts on this issue because I am getting stumped.

 
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Freeze frame was supposed to help by telling some of the conditions when it set the code so you could attempt to duplicate it on demand, but you beat it with the 5k comment and the ability to duplicate it, that's really all the necessary info now.


So the definition is CMP signal intermittent interruption, and it boils down to the computer saw an incorrect number of CMP signal pulses in a specific time/revolution period. This occurred more than 30 times in order to set the code.

If you look at a cam gear, you should see 4 large lugs protruding around the edge, plus maybe a tiny one. These are what the cam sensor "reads".



What could cause the computer to "read" the wrong number of these?

IDK....I really don't have much in the way of ideas yet, and you probably don't have access to a labscope or DSO to get a real view of the signal waveform.

You don't have an 01, there was a bulletin related to the camshaft end play causing a code problem on those.....

The high RPM was making me think maybe vibration causing brief wiring connection issues, which could lead to incorrect pulses being read.

Incorrect sensor gap or varying gap between the sensor and various lugs? Any damaged lugs? Something metal or a magnet stuck to the gear?

Remove the upper timing cover and watch if anything is moving around at 5000 RPM?


Leave the belts off of it, hold RPM at 5k and see if it still sets the code without the PS or alt and ac belts?

 
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So here is what I have: when I hold the car at 5k for 15-20 sec the car hiccups but doesn't throw a code. I brought the car to 5k and held it until the hiccup 3 times without a code being thrown. When the car hiccups it drops a few hundred (~300) RPMs but then immediately recovers. I did not remove the upper timing cover. I could do that tomorrow. Any thoughts? Unsure why the code didn't get thrown but the same hiccup is still there.

 
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Kinda sounds like it might be the rev limiter in park/neutral. Will it go higher than 5k?

 
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I just took it around 5.75 -6k when I put it in Neutral. Before I was revving the engine in Park. Doesn't throw a code or hiccup when it is in Neutral. I held it at 5.5k for about 15-20 sec. I did notice something odd: I took it above 5k twice while it was in neutral. Once the speedo went to like 30 mph and the other time the speedo sat at 0. That was odd.

Does this mean there is something wrong with the belt(s), the alternator, or PS pump? If that is the case, I will reconnect the alternator and see if I get the code back. Coincidentally, I still have the OEM belts and they are in decent condition so I could re-install them instead of the Advance Auto ones.

 
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This isn't right. Possible related clue here.

 
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What are some of the things that would cause this? I checked the primary ground wire from the battery to the chassis and engine. It is in good shape and making a good connection.

 
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Not sure yet, I've been thinking so much my butt hurts.

I wonder if you had kept the speedo reading up there longer, if the CMP code would reset?


Longshot:
Grounds, many things including the CMP and VSS share the same ground...

Check and clean (wire brush until shiny) the ground terminals, fasteners, and the cast metal at the upper radiator hose area:



The grounds on the left (pair of brn/yel wires on a single eyelet terminal) of the pic above, lead to a pair of junction blocks (also may be called splice packs) on top of the valve cover where many different groups of wires are connected together.

The same splice packs also carry the power source wires for the components in question, along with a bunch of others. Like I said, many different groups of wires make their connections within the packs.


I might wonder if any of the terminals in the splice packs are having corrosion or connection issues...... and 5000 RPM vibrations are showing up as an odd code and speedo movement?








This should be interesting...Let me know when you come up with the fix!

 
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EZ - Thank you for all your continued help; I appreciate it! :-)

I held the car above 4.5k for about 30 seconds. Here are some observations:

1) The speedo lags the tach by about a second. The speedo always moves when you rev the engine even if you only rev the engine for a couple of seconds.

2) The car didn't throw a code with the alternator belt on.

3) The first time I revved the engine with the alternator belt on I could definitely feel some vibrations that shouldn't be there. After I let off the case and the engine returned to idle, I brought the car back above 4k RPMs and the vibrations were gone. I revved the engine quite a few more times with no vibrations.

I need to clean up the ground strap connections tomorrow when it is light out. When I checked the primary ground for the battery to the chassis and engine, I cleaned up the connection to the engine because there was some corrosion there.

Where is the speed sensor on the car? Just trying to think through how the vibrations are impacting the speed sensor.

 
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Still thinking this is probably a related symptom, as I don't recall ever noticing the phenomenon on a correctly operating car.


Would be nice to have a scanner hooked up and reading live engine data when this starts acting up, see if any data goes screwy.

Was the speedo acting up prior to the belt removal?


Are the alternator bolts tight? We have bad things happen to the PCM if the alt mounting bolts are not tight.


I was thinking along the same line, but looking for something that could affect both sensors/symptoms, and I went for wiring that sits on top of the valve cover ----> engine vibration.

VSS is on top of the differential area of the transmission. 3 wire connector.

PDF link www.civicforums.com/forums/attachment.php?attachmentid=69108&d=1167777352

 
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I cleaned both sides of the chassis ground shown in the top of your 1st picture in post #14. I restarted the car. The first time I revved the engine the speedo didn't move. Every subsequent time I revved the engine the speedo followed the tach. I held the tach at 5k for about 20 seconds when something different happened - the ABS light came on. I brought the car back to idle and then I looked at the front driver's side wheel hub and noticed it was rotating. Should the hub rotate when the car is in neutral? I then revved the car a few times with my foot on the brake and the speedo didn't move.

I am stumped now.....

I am going to hook the PS pump back up and rev the engine back to 5k to see if the P0341 code comes back.

 
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*Facepalm.*

Yes it can and will spin if the car is in neutral.
I did not know the front was jacked up, has it been up all this entire time? IF so, that sure would explain why the speedo is moving.

I just assumed you had all the wheels on the ground.

EDIT: And that's probably why the ABS light came on, it's seeing wheel speed inputs from wrong number of wheels. The light should go out once you have it on the ground and drive normally again.

 
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Interesting. I didn't realize having it off the ground in neutral would allow the wheel to spin. I put it in the air to make it easier to remove the belts.

I put the PS back in the car and I reattached the PS belt. I revved the car back to 5k and held it there for 20+ sec and I revved it to 4.5k for 20+ sec and I could not recreate the P0341 issue. The only things I have changed:

Cleaned up the primary negative battery connections (chassis and engine). Cleaned up the chassis to engine ground strap connection. Replaced the new bando belts with the older OEM belts.

 
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Ok so we can skip everything since post #11 now LOL.
Back to something else....

I guess try driving up the mountain with the old belts on it a few times? IDK

 
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No worries.

I will have to drive it around through the mountains to see if the issue happens again. The good news is that the issue was there before before I tore it apart and I was able to recreate the issue. Something was causing the issue and the only things that changed were the belts and the cleaner ground connections.

You might have been right about the belts. I noticed that the OEM belts were slightly different than the non-OEM belts. The ribs on the OEM belts were solid and the ribs on the non-OEM belts were like an " M " where each rib was the M.

Thank you for all your help thus far.

 
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YW.
If this turns out to be related to aftermarket belts, it'll be a first for me.

 
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Any update on this issue? I think I am having a similar issue.