joolsbourne

Hi folks, looking for a bit of help.
I recently began getting CEL with code P0342. I changed the bank 1 sensor and noted some really crappy wiring where someone previously had spliced in a new connector.
Ran the car but still had the same code. No problem I thought, I suspect I know where the problem is....
Bought a new connector and did a magnificent job of splicing it in, going back down the harness as far as I could to ensure good wiring.
Ran the car again and now have code P0343.
I did a continuity check on my wiring to the pins on the DME.
I joined the connector wiring as I found it.

1) Any thoughts on where the problem may lie now or how/why it changed codes?
2) Anyone able to tell me the correct pin to pin wiring for sensor?
3) Whats my next step????

Many thanks in advance.
Jools

Macster

P0343 -- Camshaft Position Sensor 1 -- Above Limit.

Potential causes: Short circuit to B+.

Check the connector/wiring.

Check signal wire from DME control module, pin III/20, to CMP sensor for short circuit to B+.

1) Connect special tool 9637 to wiring harness (DME control module connector).

2) Remove connector of CMP sensor.

3) Connect voltmeter to special tool 9637, pin III/20, and ground. Switch on the ignition. Display: 0 V If battery voltage is displayed, check wiring harness for chafing and pinching damage.

Not to add to your misery but with the wiring being really crappy before you started the crappy wiring could have damaged the DME.

But eliminate other possible causes first before looking at the DME proper.

joolsbourne

Thanks for the reply, much appreciated.
Is there anything I can do without the special tool?
Any idea why the code changed from P0342 to P0343?
I have measured V at two of the CMP end connector pins. 0V at the other with ign on.
Connectivity is good with 5 ohms between each end of the cable. Is this as expected?
I wanted to check that the wires are connected correctly. Do you have the pin to pin connections and/or wire colors?
Sorry to ask more questions but I really want to fix it at home.
Would it be too offensive to just run 3 new wires from the CMP connector and splice back in near the DME connector?
Thanks again.
Jools

Macster

Before I try to answer the question why the change from P0342 to P0343 let's look at the two errors:

P0342 Camshaft Position Sensor, Bank 1 – Below Limit. Possible cause: Short circuit to ground in signal wire. Faulty sensor. DME control module faulty.

P0343 Camshaft Position Sensor, Bank 1 – Above Limit. Possible cause: Short circuit to B+.

They both can arise from a short. Just a short to a different wire.

This suggests there is a wiring problem which may not be right at the sensor connector though I'd be really thorough in eliminating that possibility but further away.

I do not know the history of the vehicle but I'm always on the high alert when a new owner finds someone has been at the wiring harness. If they've been at it once they've been at it more than once.

The special tool is a break out box. When dealing with electrical issues these are always nice for it helps one with the connecting test leads of a volt/ohm meter and making sure the connections are to the right pins and there is less chance of inadvertently damaging in this case a very expensive DME by an static discharge or by a test lead connector coming loose and shorting pins that can ruin the DME.

I do not know how much it costs but you should at least explore getting one if you are going to do anything of any consequence that involves electrical issues, and of course you are already involved.

Depending upon your relationship with your local Porsche techs you might be able to borrow one from a tech. (I've never tried to borrow one but I've had techs offer to loan me say a fuel pump test relay to test my Boxster's fuel pump.) Offer to leave a cash deposit equal to its cost with him and find out what other requirements he well requires. I'm sure there'd be a time limit on how long you could borrow the unit.

I've never done any electrical trouble shooting -- thank God I've never had to -- with my Porsches so I do not know what's involved in trying to do this without a break out box. (I have done some work with electrical circuits at work -- using scopes and other electronic test equipment in my work (firmware engineer) -- and I can tell you having breakout boxes or proper test lead pins really helps.)

As for your question about running 3 wires and splice into the harness near or far away from the DME. If you'll pardon the expression, hacking on the car's electrical harness is just not something I'd do and is not something I'd advise you to do.

You may bypass a critical fuse, or relay. The splice may introduce a voltage bias that can interfere with the proper operation of the sensor or the DME's reading of the sensor.

Try as best you can, and you really should be 100% confident, to eliminate any electrical wiring issue as a contributor to the problem/symptoms. What you find or do not find determines what you do next.

joolsbourne

Hi, I can't thank you enough for your thoughts, you've obviously spent some time on this.
I've been asking around and someone has suggested a 'euro flash' of the DME with a PIWIS? Obviously I don't have the tester, but have you ever heard of such a solution, viable or otherwise?
Thanks,
Jools

Macster

Not much time. I'm a fast typist.

The camshaft sensors should work just fine with the standard flash in the DME.

Dumping in a Euro flash just adds more unknowns to the mix.

I'm not sure in this case it would help. IIRC one reason for using a Euro flash is it does not support the monitoring of the #2 O2 sensors and this is one way to get around sub-par after market exhaust/converter performance without having to stare at a CEL all the time.

Based on what you've posted there's a wiring problem. To do it right you need to find this and fix it. (Or if you find it is something else fix whatever else it is.)

Byprodriver

Euro flash was recommended because it only monitors 1 Cam sensor. Not sure if that would help your problem but it would be much better & probably cheaper to have the problem fixed properly.

joolsbourne

I'm still working on this, really appreciate all help so far.
As I know the wiring was cut previously near the connector I'm still unsure as to the correct wiring. I really would like to be 100% that the pin to pin connections are correct.
Does anybody have a DME wiring diagram or can tell me the wire colors or pin to pin connections?

Macster

I have hard copy of the Boxster factory manuals and in one (very large) 3-ring binder is all the wiring diagrams, though I do not know to what year the diagrams apply.

Sunday AM I plan on being in the office -- the manuals are stored under my desk at work -- and I can make a PDF of the sheet that contains the wiring layout to the sensor and which has the wiring colors labeled. Send me a private email with your email address that can accept a PDF -- I do not know how big but it won't be super sized -- and Sunday I'll send the PDF to you.

joolsbourne

That would be great, thanks. I'm at joolsbourne@hotmail.com
I can't tell you how much appreciate your help.
Rgds,
Jools

Flat6 Innovations

All too often people think that a code is the SOURCE of a problem, when its nothing more than a symptom of an underlying condition.

Check for camshaft/ valve timing deviations and go from there. I always default to what underlying conditions can lead to a code, not the part that code is directly related to.

Macster

No disagreement from me. In this case though the OP reports someone's been at the wiring harness in grafting in a sensor IIRC and in trying to deal with this the error has switched from one type of a ground error code to another which suggests a wiring issue is still present.

Now once what is assumed an electrical issue is addressed there might then appear an error code that points to the timing of the camshafts and then certainly that is not the source of the problem, only a symptom of the underlying problem, just as you said.

Flat6 Innovations

Yep, I am with you.. Someone hacking into the harness could easily be the entirety of the issue with this one.

Here we always go straight to the possible underlying condition and prove that its not the issue before doing the simple stuff. OBDII scanners cost people a ton of money who read a code, decipher it as XX sensor and then go buy that sensor, only to have a continuation of the same issue.

Its just like a MAF sensor code can actually be a vacuum leak, or a bad AOS, but because the ECU has added as much fuel trim as it can to try and solve the problem, the code thats thrown is for the MAF, but the MAF isn't the issue.

Hacking on harnesses isn't for the novice.