02 Honda Civic P0340

KbarC

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Ok. I will do whatever i need. I appreciate the help immensely. That said, i have to ask, are these elm327s car/make specific ot will anyone do or do i need one with any specific features??? Thanks again
 

billr

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Those ELM devices are not make/model/year specific, they are just an interface from the OBD2 communication standard (mandated to be same for all) to your PC/phone. The only caution I know is to step up to the "big bucks" for whatever dongle you buy. Those under about $25 (and there are many) tend to be clones that may not work properly in all cases.

Where you will find quite a bit of difference is in the software you will use on your PC/phone. My understanding is that there are several good free or very low cost options there. You need nickb2 to advise, but I expect most will handle a wide variety of M/M/Y. Probably all SW handles the "basic" OBD2 and associated live-data. I would be looking for SW that does ABS, transmission, manufacturer-specific, bi-directional, and data-logging.
 

nickb2

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I fear there is some misinformation in the above. The driver for the CMP (or CKP) signal will be in the sensor, triggered by a Hall device in the sensor. The PCM side of those circuits is a high-impedance that is so well protected and so low power as to be nearly bullet-proof. The first transistor that signal is likely to see on the PCM side will be inside the PCM CPU chip itself.
yes, thx billr,I knew I was writing something wrong, and I knew someone would autocorrect.

That is why I asked for cam and crank sync. Anyway, this is a very interesting thread and I like the newbies approach, he gives me faith again in this site.

Ok, I am off for real now, later I will post what I found on mitchel. But right now, watching a cool movie with 1 loved one, .

The movie is real cool, a bit disney, but sure feels good to laugh and cry at same time. The movie is called (the call of the wild) There is even a french guy in it.
 

billr

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Get the OP pointed to some good SW, so the dongle can be used as soon as received.
 

JackC

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@billr. This reminds me of our experience with my Buick cam sensor- magnet problem that you figured out for me. I will never forget how grateful I was for your assistance.

@KbarC Hang in there, these guys really know their stuff. Double check your info, spelling etc. Reread , correct, etc.
With your patience and proper testing they WILL help. As long as you want them they will be there.
 

nickb2

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@billr, I love this link, it is updated quite often to my surprise. The more these dongles are being massed out, the more they are open sourcing it. Most are free.

I did say MOST right. ;)

In today world, we have to disclaim everything for fear. Anyway, I dont know his level of PC skills, but some really good kernal stuff has gotten open sourced.

https://www.elmelectronics.com/help/obd/software/

Internet is real slow up here, my patience is wearing thin. To many ppl on the net, but this link should provide a variety of options for op. Most of what he can do with the dongle will depend on which version chip he bought.

I could not access remotely mitchel, so sadly, cant get a better schematic right now for him. I will try again later.
 

nickb2

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IDK bill, looks to me it is in the ECU on schematic. It seems to be a NPN bipolar. But at this point, I will probably just confuse issue.

Ok, after some patience, finally got it. Here is a much better pin out and better component guide.

Hope I can upload it for op. At others who here know me, I can no longer use bullzip pdf, for some reason my new pc build with rysen 7 chip does not agree at all with it. So I found using your browser of choice was the most optimal to transmit data and I will continue to do so as it really seems to work and still in pdf format.

;)
 

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nickb2

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I used CKP chart as billr mentioned that and found it was better than all data.

I after all this is done, op will need to confirm ecu failure, then we can proceed to tell him how to circumvent a vin mismatch.

For this, he will need a high end scanner like a few I own or use, or go to a reputable shop that can actually do that.

I am hoping it is not the ecu, but my gut is telling me, this is one of those rare occasions.

Of note, an idle relearn is a absolute must. More to follow later when op posts back his findings. I am used to being up early, now no work to get up early to. But learning some cooking skills, making a scandanavian omelette. Wish me luck, I have no idea what I am doing, but massive time on hand to figure it out. :p

 

billr

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Referring to the PDF in reply #52:

page 2/14 shows PCM connector pin A7 as being the CKP signal... note that it is BLU

page 3/14 shows pin A26 is TDC signal (GRN)... there is no listing for CMP, so I am thinking TDC = CMP for this system

page 11/14 shows the CKP connector pin-out as:

1 = signal (BLU)... this is consistent with page 2/14
2 = GRD (BRN/YEL)... I assume this means "brown wire with yellow tracer stripe/dots"
3 = ignition voltage (YEL/BLK)... this is a big hint that the sensor pull-up is in the PCM or that there is active signal-conditioning, like a transistor, in the PCM for that input

As I proceed down page 11/14, into the "Tests", I get lost. The tests all refer to YEL = CKP+ and BLK = CKP-. Do you see how those colors are not consistent with all the previous color notations??? Also, that "CKP+/-" notation is more typical of a VR (variable-reluctance) type sensor, not the Hall type that seem to be on this engine.

OP, my confusion is probably not pertinent to your problem. I am just flagging it because when some things in a document don't seem to "add up", then I am wary of the whole doc. This post will keep nickb2 and myself amused here!
 

KbarC

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Bill, You are a mind reader!!! I was just looking at this and scratching my head my head.... i will just go with pin#'s and not color and see what it get.
I can attempt the testing and see what i get voltage wise. i have no way of actually watching signal as everything today will be via volt meter. I will post back later and yall can let me know it you think it is worth throwing a crank sensor at it.

3 = ignition voltage (YEL/BLK)... this is a big hint that the sensor pull-up is in the PCM or that there is active signal-conditioning, like a transistor, in the PCM for that input
ummm..... in English please lol
 

billr

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It is hard to say about the CKP sensor, it will depend on how you value time vs. $ Now that I know Honda probably uses "TDC" to mean "cam" and not just the crank position, the CKP sensor seems less likely. However, you may end up having to throw something at it anyway, either the CKP sensor or PCM. The CKP is cheaper, so I would start there when it is time to "throw parts".

Let me try to explain... There are only five real possibilities here. Bad CKP sensor, bad TDC (CMP) sensor, bad PCM, bad wiring anywhere in the system, and bad "mechanicals". By mechanicals, I mean a damage trigger wheel or horribly sloppy cam drive. Since the engine operates OK cold, I think we can dismiss the possibility of a mechanical problem. The basic innards would not change so easily with just temperature. The VTEC is one unknown to me there, but I would not expect there to be any point in the VTEC range of cam timing that would result in an invalid TDC signal.

You have already fed it a new TDC sensor, so I think we need to look elsewhere, for now.

Chasing/ checking all the wiring and connectors can be a tedious and not always conclusive task. You should certainly look for any obvious problems, but proving the wiring is OK may take replacing it with known-good (if even temporary) to see if there is a change.

Once you have exhausted your efforts to check wiring, presumably with no joy, you will then have to replace either the PCM or CKP with a "known-good" unit (or try another TDC sensor).

The only definitive way to find the problem, without some part-swapping, is to use an oscilloscope to trace the signals. There are some fairly inexpensive scope options now, if you want to invest in that kind of equipment and skills.

As to the "hint" I get from the fact that the CKP sensor is powered by "ignition"... that may get tough to explain, but I will give it a try.

The CPU in the PCM is most likely going to work off a 0-5V digital signal. Most Hall-type CKP sensors can be powered by a wide range of voltages, but the two most common are either the 12V (battery) or 5V from the PCM. If the CKP sensor is powered from 5V, then it can conveniently send a 0-5V signal almost directly to the PCM CPU. If, however, it is powered from some other voltage (like the ignition 12V), then it is most convenient that the signal line produce no real voltage, but merely be a wire that switches a 5V signal from inside the PCM on-off. Or, the 12V-powered sensor could produce a fairly dirty 0-12V signal, but that then has to be "pre-processed" inside the PCM to clean it up and reduce it to a nice 0-5V for the CPU. Clear as mud? I tried, just not so good with words!
 

KbarC

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Thanks and yes, somewhat clearer. It does, however, reinforce my liken of old school carbs and point style ignitions. A couple wires and couple hoses that's it lol and no this is not the Vtec

Yes running so good cold makes me believe it is good mechanically. i even made sure cam timing was good just for fun and it is dead on!

I don't mind investing time in building skills, especially right now while sitting around because the planet is closed the last 3 weeks. Thing is i am trying to not invest money for the same reason.

all i know about this crank sensor is i have 12v to it, 5v signal and one closed to ground.

I will continue probing and checking values. Curious if there is anyway i can check PCM without swapping. I would have to buy and have shop electronic deal with new problems of different PCM hoping that does it!
 

KbarC

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a little more info..... I went ahead and threw a crank sensor at it ...NO HELP!!
Everything checks out while it is running good. However, once it throws the code and goes to running like crap, I have no voltage at the A26 pin.
 

nickb2

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Ok, got some better wirings, since I never asked which model it was, I just included them all from AT to MT

Hope these help, and yes bill, honda does mean cam sensor but they call it TDC sensor.

I just wish sometimes all the nomenclature was standardized, it is even worse in the EV cars. Alot of the guys when I go to my courses fumigate. I am lucky, I am somewhat bilingual.

So, now, we need to check common grounds. And yes, the ckp and TDC aka cam sensor use same ground also with the IAC. But since the car is running and idling and just throwing a TDC code repeatedly, the ground choke point is most likely to be ok. And now we also know it has a knew ckp sensor as well.

So, if op is sure pin integrity in pass through slash JC104, he is getting 12 volt there, and if he checked that with ground, and still no joy, and ohmiing from tdc sensor connector to pcm slash ecm, only one thing left really, driver is on fritz in pcm for this sensor.

At this point, I am again parroting myself, but enjoying this newbie, cuz you know, I hate when ppl just flip us off and dont follow advice, they have a special place in hell like the ppl outside trying to make a quick buck off this covid thing.

Can you believe the emails I am getting, phone calls for special life insurance, asking to donate to phoney funds, selling phoney masks and trump 3m stuff. Happy 3m stood up, happy trump came back to senses and reverted course on that with its best neighbor.

These ppl should and will rot or soon will be taken out and shot on site. Ok end of rant, here are those wiring. Sorry, but again, even though extremely rare, this ecm seems shot.

Also, I really liked the new vin diesel movie bloodshot, dont know why it got such bad reviews, it was awesome on my home theatre. The action scenes were on par with some of the best cgi I have seen in a while.

I add this here because I know you guys are really getting hit hard, and finding good movies to watch to stay home is key to keeping sane. Especially if your like me and live in an apartment with no garage.


Btw, that scandanavian omlette was really good, will put that in my weekly diet for sure.
 

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