Fixed the leaking heater hose on the back of the engine today. Had to remove the intake to get to it. New intake gasket from the dealer installed along with the new heater hose. Everything was strait forward not to bad of a job. Test drove, no leaks everything working again.

Tell the wife its fixed so she runs to the store with it. I see her walking up to the house with no car! She said its down the block as it stalled in the intersection, then restarted and stalled again. Very nice! I walked to it and it started up for me and I drove it home. I was throwing a code-engine electronics-PO725 Crank postion sensor.

I cleared the code and I have looked it up in my MB CDROM the sensor does sit about a foot below the hose I replaced. I can see it but I will have to remove the intake again to get at it. I am wondering if I should try and replaced this now or run it again to see if it throws a code. I don't think I even touched this when I put the new hose on but maybe the antifreeze leaking messed it up. Anyone have any problems with this sensor?

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

Perhpaps you disturb a connector which is what feeds from the CPS...can you see if there is any wiring that you can get to? If coolant dripped into the electrical plug it is possible that is what is causing the problem too...maybe just let it dry out some and see what happens.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

good point. coolant did run down to the ground when I pulled the old hose so that is probably the problem. I will pull the intake back off tomorrow and get the sensor out and look at it.

Wife is really wanting to dump the car now- 3rd time it has stalled on her, we purchased the car 2/07. I really want to keep the diesel but I can't blame her I guess. I hope I can talk her into a 99 E300 when I sell it.

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

See my comments in this post about replacing the CPS:

http://www.peachparts.com/shopforum/showthread.php?t=188064

It can be done on a 96 without removing the intake.

The CPS connector is contained within an L-shaped rubber boot, so I doubt a little spillage of antifreeze (or water, or anything else) from above would cause any problems at the CPS itself. Maybe, as nhdoc suggests, you disturbed the cable from the CPS somewhere else.

Thanks pjc-
I think I need to remove the intake just to see if I did distrub anything that feeds to the CPS. I find it hard to belive that some coolant would get in there with that boot over it as well. From were it is I am sure I at leat brushed agaist the wire when trying to get the hose on. I hope I find something unpluged (I doubt it will that easy.)

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

Well I pulled the CPS sensor today and coolant did make its way into it. You can see the dried coolant on the conection pin and all over the outside. I tried to clean it up and put it back in but its fried. As soon as I started it up the engine jumped up and down and then shut off.

Will be calling the dealer in the morning to see if i can get one.

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

It's a shame, but on the bright side you have isolated the problem and it's probably not that expensive a part to replace. The thing to remember is if a small spill of coolant fried it then it was probably not too well sealed to start with. Bite the bullet, replace it and you'll probably be back on the road in a very short time. Don't be tempted to throw in the towel on a car just because it has a few issues. Every used car has issues and it took me 2 years to get my '98 running well and to get everything up to snuff on it. Now it is as reliable and drives like any new car. If you get another one you'll just be starting over again.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Interesting. I've hosed mine off rather seriously many times in the past paying special attention to the rear of the block and top of the trans directly above that sensor and never had an issue. Guess will start being more careful next time I hose it off.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

I agree Doc I will just be starting over with another one. I would prefer to keep it. I understand about used cars and getting all the bugs out of them. In fact I think I have this one in pretty good shape. I have worked out the following problems-
1. the engine temp problems-new electric fans and fan clutch
2. fuel filter seal leaking air problem
3. This leaking heater hose and now the sensor.
The car has all new fuel lines and seals, running synthetic oil. I really like this car but my wife is the one who drives it with 2 small kids. She said she is never driving it again so dont have many options. I have already expained to her that if we get antoher one it will have problems-its a mechanical thing someting will go wrong. I am trying to talk her into a 99 E300 so I get the turbo I am in a dilemma- How to keep my love for diesels and keep my wife happy-I dont want to end up with a toyota or smilar.
She is back to driving my gas hog Dodge Ram now-the only reason I have had no problems with that is because it is to new low miles.

Terry- I thought the same thing, why would the sensor fry? I have hosed the engine down also and nothing went wrong. Maybe it has someting to do with the coolant intead of water getting the sensor

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

Do you have a digital multimeter? I'd be interested to know what readings you get from your old CPS that you say is fried.

Before I get to my readings, though, perhaps another member on the board can confirm how the car uses this device. The inside tip of the CPS is magnetic, which means two things: First, its resistance will vary slightly based on its proximity to a large metal object (crankshaft). Second, it should generate a very small electrical current when the crankshaft (or part of it) comes close enough to disturb the magnetic field. But to generate any current, the crankshaft would have to be moving, so I'm guessing the car uses the CPS as a variable resistor.

Since replacing my CPS did not solve my no-start problem, I believe the one I pulled out is still good (has MB marking, may be original). Its resistance is 720 ohms, increasing to as much as 760 ohms when I bring the tip close to a large metal object (cast iron frying pan).

How does yours compare? And can you see any physical damage to yours (other than a coating of antifreeze)?

I do have a digital multimeter but I have not checked it. It is back in the car and I was not going to pull it until I get the new one. I guess I could pull it out and check it. the code it is throwing is PO725 (or P0335 in MB terms)which is the CPS- I know if could be something else causing this but like you I figure I will just get the part and try it. Are you saying mine should be getting the same ohms? I checked the CDROM I have and it says it should resist 600-1200 ohms so it sounds like yours is good. I wish I would have know about this earlier I am too tired now to go pull it. Maybe I will wait to order it and pull it tomorrow after work to check it.

I did not see any physical damage to it just the inside pin and connector coated. I do not know enough of how this sensor works to understand how mine would go bad from the coolant but I hope that is the only problem.

__________________
1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

I ordered the part and it will be at my local dealer wednesday.

For the hell of it I pulled the sensor out to check the resistance. I set the mulitmeter to 2000 ohms, but I get nothing- what are you touching to what to get your readings? either this thing is gone or my multimeter is not working


update-I think I got it it is reading about the same as yours 720 but when i move it to the cast iron pan it jumps to high 700s 850 back down to 650 and all over the place.

I am getting this sinking feeling that when I put the new sensor in it will not fix the problem.

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

Hard to tell whether that range of readings is caused by the sensor alone, or by the ohmmeter probes moving around a bit as you're holding them gingerly against the center pin and side wall of the CPS. As you surely noticed, it's pretty hard to hold them in place to get any reading, let alone while you're moving it back and forth. I used an alligator clip for the center pin, which made it a little easier. And, of course, I don't know what the spec readings should be; I just wanted to see if the resistance would change, which it did.

My bet is the new sensor will fix it. It's possible your sensor has an intermittent short or long circuit condition and just twisting the wire or holding it differently clears it temporarily. That explains some of the problems you have reading it with a VOM.

If your OBD code was for the sensor it is most likely what is at fault. They throw a code when the circuit is shorted or opened, which would also cause your no-start. You might have bumped the wire when you were working in that area and caused the problem to surface...just replace it and keep your fingers crossed...I'd bet it will start right up.

I'd bet these work the same as an ABS sensor, they work by the hall effect and the moving crank induces a small voltage that the sensor sends to the CPU. Report back once you get the new one installed.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Let the woman get her own car. Problem solved.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL