[brianprentiss]

Got my wife's 02 Turbo with 130000 for a song. Turns out the seller may have been happier to get rid of it than we were to find a bargain. It ran fine for about 2 weeks after we bought it and then one fault code after another over the last 2 years.

So far have put in new coils and plugs, have replaced the throttle body, replaced plastic hoses that were cracked and throwing secondary air intake codes. And, taken out crappy wiring for after market radio. So, obviously a less competent DIYer had this previously.

But, now I have THREE major issues that may or may not be related:

1) The car will run fine cold, sometimes for a few miles sometimes 10, but then it will sputter and die. The interior lights stay on but I can't restart the car. Nothing happens. But, if I come back to it 24 hours later, it will crank presuming it has enough juice. Which leads me to...

2) I can't keep the battery charged. I've had it checked twice and charged it overnight myself. Charged to 13.68 amps and while sitting outside the car the battery decharged slowly to 12.68 over a week. I charged it again and put it back in the car but pulled out all the likely fuses with the intention of trying to pinpoint which one the causing the parasitic drain. I was in the process when I needed to drive it. It ran okay but...

3) Check engine light came on and I noticed the car wasn't starting in 1st gear but 2nd. I could force it into 1st by shifting there but it wouldn't to into 1st on it's own. It started losing power and stalled. Would not restart. 24 hours later it restarted and I drove it home where it sits now and doesn't have enough power to crank. The battery reading is now 11.80!!

Present codes are:
0725 - Engine speed input circuit
1780 - DTC definition not found!
1850 - " "

and the 0411 ghost which I've been chasing since I bought the damn thing. The hose I fixed is fine.

My first guess is that I have a faulty crankshaft sensor, but I can't figure out why the hell the battery keeps dying. The ABS also started blinking so I'm wondering if given all these problems if perhaps I just need a new ECM.

Any suggestions, or it's definitely not that, or try this would be appreciated.

 

[billymade]

You have a number of codes; they are generic OBD II codes, which are not vw specific or have a definition on the Ross Tech Wiki. Keep in mind: it would be helpful to access VW factory codes with a VW specific scan tool like VCDS by Ross Tech or equivalent scan tool. This is a worthwhile investment and will help you repair your VW yourself and save you thousands of dollars, in fees, from pro shops or the vw dealer, diagnosing the problems for you. VCDS by Ross Tech is highly recommended and is the gold standard, by which the others are judged.

https://www.obd-codes.com/p0725

This trouble code, makes sense; in relation, to your hard start or no start condition. The engine speed/crank sensors; failure modes, are typically very much related to temperature, as when a engine is cold, it can work fine and once up to operating temperature, will start failing, intermittently working correctly or just stop working all together. These problems, can happen occasionally; then, as time goes on, get worse and eventually, not start at all. Replacement, with a high quality oem Bosch sensor; is typically, the fix for this.

 

[billymade]

https://www.engine-codes.com/p1780.html

Based on this code, it seems to be transmission related and coincides with your shifting problems. This is another case, where a vw scanner; probably, would give you a vw factory code and narrow down the issue. On the automatic transmission; it is common for the selector to fail or the internal magnets, to come unglued, the tcm does not know, what gears are being selected and this can cause a shifting issue(s). This, is just one; of many issues we typically see, problems range, from failed sensors, wiring issues and even failing solenoids in the valve body. Again, a scan with VCDS; should shed light, on the source of the problem and pinpoint, areas to test and check to solve the malfunction in the system.

 

[billymade]

http://wiki.ross-tech.com/wiki/index.php/18258/P1850

Another code, confirming possible electrical problems and the fact, that communication to the ecm, is being interrupted.

 

[billymade]

http://wiki.ross-tech.com/wiki/index.php/16795/P0411/001041

We continually see secondary air injection issues; one must work down the list of possibilities listed on the ross tech wiki definition and test, inspect, each one until you find the problem.

 

[billymade]

So, you have your work cut out for you; from what you are posting and the codes thrown, you are having multiple issues with a number of problems. Getting access, to a VW scan tool; would be helpful, narrow things down and give you more specific insight, into the causes of the problems.

To being with, I would probably; start with the crank/engine speed sensor and see if you can resolve that. After that, then you might work on getting a vw scan tool and driving the car to a auto parts store, have the charging system, fully test and confirm everything is working as it should (battery, alternator, are good etc).

Then, at that point; hopefully, the car would at least run, to the point, you could scan it and start working on the vw codes, transmission shifting issues. Lastly, the secondary injection system; is a matter of testing and confirming, things work, finding the offending part, that is at fault for the trouble code.

Let us know, how you want to proceed and if you want to fix things yourself or have a shop handle things. We can go from there, thanks!

 

[brianprentiss]

thank you! This is really helpful and exactly what I was hoping for.

 

[brianprentiss]

I changed out the crankshaft sensor, which was quite a feat. Unhooking the top is easy but getting a socket wrench up into the cavity where the bottom is screwed took a LONG time. Even after unclamping some hoses I had to lay on my stomach and reach up there and do it by feel. Were I to do it again I would have done an oil change so I could have removed the oil filter.

The bad news is it didn't help anything. Still starting in 2nd gear not 1st. I'm going to change the trans fluid and filter next and see if that helps.

The possibly good news is that when unhooking the top wiring I noticed that there was a loose wire disconnected from the top of the alternator. The clip was broken so I had to zip tie it, but perhaps that's why the battery is not staying charged.

 

[billymade]

Well, a crankshaft position sensor; is a ignition parts, so I would not expect it to "fix" a tranmission/shifting issue. I recommend, that you get the car scanned with a vw specific scan tool like the ross tech vcds scanner; this will enable you, to read any codes, that are stored in the transmission control module. As noted before, we see these issues with shifting problems: failing/sticking solenoids in the valve body, wiring harness problems (internal/external), bad external sensors and the shift selector failure, causing the tcm, to not know what gear it is in. Many, end up need to replace the valve body; this has cured many shifting problems for people but you always, want to look for any codes first, confirm, what the problem is, before replacing parts.

Changing the fluid; may or may not fix your problem; before buying a trans fluid kit, it is advisable to do more testing and troubleshooting. If you end up having to replace the valve body; you will have to do a fluid change anyway, so keep that in mind.

The crank speed sensor; can be a challenge to replace and that is good, you found the broken plug on the alternator. You can buy new plugs at your local vw dealer or get the part # off the old plug and look online, for a pigtail style with the wires, splice it in or just use the plug portion, as a replacement.

Get your car scanned with a vw type scan tool; report back, what codes you find and we can go from there. Thanks.

 

[brianprentiss]

I frequently read people on this forum recommending getting a scan an "an auto parts" store. Do they typically have VW-specific scanners or just generic?

 

[Smileybug]

They have generic scanners, but its free and a good start.