P0340

[Southernboy]

The title refers to the error code for intake cam sensor malfunction.
Anyone with any insights, please add to this post.

So far......

1. I watched the video you posted the link to. (Nefyn cat posted a ;ink to a video and below is the subsequent reply I made, and the action I have taken thus far.....)
   
   #5Southernboy, Yesterday at 9:51 PM
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2. 
   Did you notice the difference between the Meyle replacement sensor and the OEM. The OEM sensor shaft is considerably narrower in diameter than the Meyle sensor. Now here's the rub - I was reading a post on Bimmerforums regarding a P0340 fault code issue. The OP replaced the sensor with a non OEM sensor which was exactly like the Meyle sensor - fat vs thinner OEM.
   Anyhow, the result was that the replacement sensor didn't resolve the PO340 code. The OP obviously didn't know how to test the OEM or new replacement sensor, and decided to buy a new OEM sensor, which after fitting appears to have resolved the P0340 code issue.
   He made the conjecture that it might be that the fatter non OEM sensor wasn't reading the signal as sharply as the OEM sensor because of it's larger diameter. In other words, he was suggesting that the larger diameter meant that the proximity disc on the cam was actually being read for a longer duration than would be read by the narrower diameter OEM sensor.
   Now we get to the nitty gritty part... I posted this tip because I had an OEM sensor fitted and had the P0340 code come up. Before I learnt how to test the sensor as per my tip of the day link, I bought a Meyle sensor and that is currently fitted in the car. The P0340 code still comes up... So, this weekend I'll do a test on the Meyle sensor, a test on the connections for power, ground and signal lines to the ECU, and finally a test of the original OEM sensor. This I hope will resolve the problem clearly, since there are only 2 areas that can be at fault - 1. the sensor, and 2. the connection of the sensor to the ECU.
   To quote the code fault wording on the scanning tool when it showed the fault on my car it showed- "P0340 DME SIGNAL - INLET CAM SENSOR".
   That seems to indicate to me that there may be a fault on the signal wire from the distribution box under the intake manifold where the cam sensor wire connects. This is testable with a multimeter, as are the power -positive voltage and the ground line, either of which could also be the culprits. A weak voltage, or poor ground would affect the signal strength as much as a poor connection of the signal wire to DME.
   Fortunately i still have the OEM sensor with the narrower diameter tube section, and if I find it is working to spec, I will then be persuaded to look at the connectivity from the distribution box to the DME and the positive and ground connections.
   I still have the "old fashion" multimeter with a needle indicator, so went out and bought a digital display model today... with nice big digits so I can see them even without my specs...
   As far as the "mooted" larger diameter vs the thinner OEM idea goes, this doesn't make sense to me, and it might well have been a connectivity issue between the sensor plug and the connector at the distribution box. The fact that the Bimmerforum OP, effectively replaced the sensor twice, that simple action may have cleaned away any oxidation or whatever which may have given rise to the problem originally.
   As part of my plan this weekend, I'll certainly use some switch cleaner on the connector at the distribution box as well as the connector on the sensor lead, just to make sure that the problem isn't at that contact point.
   No doubt that the P0340 fault is causing me issues, because i do experience bouts of weak engine power which I am attributing to the cam sensor... Hopefully my effort will be rewarded and I will have resolved the problem - I'll let you know what the outcome is.
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   SouthernboyZorg Guru (II)
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   So, both sensors check out as good. Next, I checked the ground wire connection at the small distribution box connector - all good.
   Next checked the power supply connection at the small distribution box - all good.
   Finally, removed the DME and all connectors and gave the DME pins and all connectors a good spray of switch cleaner. While I was in there, I removed / disconnected evry other connector / relay etc and gave them a switch cleaner blast.
   Everything is now back together and I'll pop over to my mate with the scanning tools on Monday to check / clear codes. If the code is there, I'll clear it then restart the car, take a short drive and re-scan. Hopefully the problem will be sorted and has been a connectivity problem.
   If it is still throwing up the code, I'll move on to the crankshaft sensor and related wiring, as it seems a faulty crank sensor can cause a "faulty cam sensor " code to show. After that it becomes expensive since I will need guys with oscilloscopes to check the wave form, and the pulse from the DME and sensor.
   And finally, I have just read that it may be that the cams need to be re-timed... So, a long road ahead it seems...

 

[Eddie Zedder]

I can tell you that genuine replacement BMW sensors are the fatter type and superseded the thin ones. Seem to remember reading somewhere that the thinner ones had issues with signal transfer as they aged.

 

[the Nefyn cat]

Cam timing not a big job, so long as you've got the tools. If you haven't got them, don't even think about it. I bought a set a few years back, still only used it once, but may get round to at least checking the number two cars' timing. Chains stretch after a bit of use, wouldn't surprise me to find out there's a couple of degrees gone missing over the years.

 

[NZ00Z3]

I've worked on the P0340 code twice now.

Daughters E46 323i with M52TUB25, fitted Meyle sensor. Car runs well, still gets the P0340 code every now and again when there is a long crank. Just stop cranking and give it another go and it fires straight up.

Friends E46 328Ci with M52TUB28, fitted Meyle sensor and it did not fix the problem. Fitted BMW labeled sensor and problem solved.

I'll only buy BMW labeled cam sensors now.

 

[Southernboy]

I've worked on the P0340 code twice now.

Daughters E46 323i with M52TUB25, fitted Meyle sensor. Car runs well, still gets the P0340 code every now and again when there is a long crank. Just stop cranking and give it another go and it fires straight up.

Friends E46 328Ci with M52TUB28, fitted Meyle sensor and it did not fix the problem. Fitted BMW labeled sensor and problem solved.

I'll only buy BMW labeled cam sensors now.

Now isn't that a coincidence Murray - both cars are M52TU models - as is mine ??
Do you think this is significant ? I have never ever had the code on the M54 3.0 or the M52 2.8.
You also specifically mentioned "cranking" with regard to your daughters E46.
I have found that sometimes, the motor fires immediately, and other times it won't and I have now become aware of the cranking issue and try to avoid it, but sometimes I catch myself doing an extended crank and stop immediately.
Your observation that a long crank initiates the error code is interesting.
Perhaps I should look into the plug coils and check them for correct performance,
I'll be removing the injectors next weekend to get the 100% cleaned / serviced...
And the fuel pressure regulator is also on my radar for test / checking since I find that if I switch on / off / on / off before cranking. this extra initiation of the fuel pump cycle seems to help for an instant start-up.

 

[the Nefyn cat]

Not that it's going to help at all, but both my Z3 (M54 2.2) and the e46 (M54 3.0) have given me P0340s. Done the Zs, not got round to the 330s yet, but it doesn't seem to have made any difference to the way it drives, foot to the floor and off it f**ks, pretty damn quickly. Don't understand, the Z gave me the code reading and ran like a very sick puppy indeed, didn't want to start and when it did get going it certainly made its displeasure known. Which is why I'll be testing the sensor before hurling a large chunk of money at the dealers.

 

[Southernboy]

Quite a confusing issue. I have found that the problem of lack of power only seems to happen after I've done some considerable amount of driving in one stint, but if I stop and re-start 30 mins later, she's good again. Next day, with a cold engine, she's all go again. Maybe I'm missing something here. But the error code keeps returning.

 

[NZ00Z3]

The inlet cam sensor is used for ignition timing. The back up sensor if the crank sensor. I found that if the cam sensor was playing up and didn't give a signal that a long crank resulted. If you continued until the engine fired using the crank sensor for ignition timing, then you were down on power as the VANOS was not active due to the lack of the cam sensor. Thus on my daughter's E46, if we get a long crank, we stop and try again until it fires straight up. Usually the very next crank.

If you are loosing power after a long stint of driving, it sounds like the cam sensor is failing when very hot.

 

[Southernboy]

Thanks Murray. Are you suggesting I should try replacing the cam sensor again with an OEM part ?

 

[the Nefyn cat]

I used an OEM sensor straight from BMW on the Z when it died, but may try the Febi ones on ebay for the coupe. Less than half the price of the genuine ones, but not so cheap as to worry me too much. I believe it's a hall-effect sensor, not particularly complicated, really, no need to cost as much as BMW want. And it's only my money I'm wasting if it turns out to be cr4p.

 

[the Nefyn cat]

So there I was on Thursday, ready to go on holiday in the coupe, and the cam sensor decided to die. Didn't want to start, and stalls once it's running, seems about par for the course with these. Luckily I only fitted a new sensor to the Z a couple of months ago, so rushed off and swapped the sensors over. No more reluctance, and the car got here just fine. Derbyshire, that is, we know how to do exotic. May yet go for the Febi sensor when I get home just to see if they're any good.