# P0321 Problems New Sensor Failure



## Vabeachtennis (Aug 27, 2014)

Hi,

2002 MK4 2.0 engine. The called stalled when diving on the highway , it was 90 degrees . I had to get towed, it would crank and no start. I checked the car the next morning,with a code reader and got P0321. The car started up right away but the EPC light was on, I ran it for a minute and then turned it off. I checked it the next morning and it started up just fine with no EPC light. I was able to drive it to mechanic's a mile away and it ran fine like nothing happened before. 
I bought a sensor , had it installed, picked up the car and drove it to the store and then home. It ran fine. 

The next day I took it for a 6 mile ride to the store, it ran fine. When I came back out to leave, it had the same no start and p0321 code. I know they replaced the part because they gave the old part to me. Could it be a defective part or does anyone have an idea of what the problem could be?


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## Nugget Beercase (Jul 10, 2016)

From the ross-tech website regarding P0321:

_When an engine will not start due to mechanical (spark/fuel/compression/timing) related issues it is not uncommon to set a false G28 fault codes due to extended cranking with a no-start condition. _

Could be lack of fuel (pump on its' last legs?) or something else causing a no-start.


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## Butcher (Jan 31, 2001)

Sadly, just because the computer gives you a code, does not mean that anything is bad. It's only giving you information for you to make a few tests to confirm the part is good or bad. 

You mentioned that you replaced a sensor, since there are several under the hood and even more throughout the car, which one was it? Did anyone perform a diagnosis before anything was replaced? Is there a reason for that?


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## Vabeachtennis (Aug 27, 2014)

Nugget Beercase said:


> From the ross-tech website regarding P0321:
> 
> _When an engine will not start due to mechanical (spark/fuel/compression/timing) related issues it is not uncommon to set a false G28 fault codes due to extended cranking with a no-start condition. _
> 
> Could be lack of fuel (pump on its' last legs?) or something else causing a no-start.


Thank you. I replaced the fuel pump a couple of years ago, when I had the no start because of the fuel pump, there were no codes even after trying to crank it a few times. It started up and ran good this morning (like the other mornings), I let it run for a few minutes and no problems.


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## Vabeachtennis (Aug 27, 2014)

Butcher said:


> Sadly, just because the computer gives you a code, does not mean that anything is bad. It's only giving you information for you to make a few tests to confirm the part is good or bad.
> 
> You mentioned that you replaced a sensor, since there are several under the hood and even more throughout the car, which one was it? Did anyone perform a diagnosis before anything was replaced? Is there a reason for that?


Thanks for your answer. I had the G28 aka crank position sensor replaced. It is located by the oil filter. The car just stalled out on the highway and when I got home I looked up the code and it showed to be the G28 sensor. I ASSumed that with the easy start when the engine was cold and the no start after it was warm, the problem could be what I have been reading in these forums and in the Google search. The old sensor had 197k miles on it, so I figured it only made sense to replace it. The replacement was a Bosch sensor. 

I'm going to test the old sensor with the multi-meter and try to confirm it's condition.


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## Vabeachtennis (Aug 27, 2014)

I started the car up again this morning and it started ok but the CEL starting blinking and I got a P0301 misfire code. The blinking stopped in about 5-10 seconds and then stopped. It happened to me the other morning as well, both morning were pretty humid and damp. Could this possible point to the coil? It used to misfire like that when I would start it up and it was foggy out.


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## Butcher (Jan 31, 2001)

ALL electric fuel pumps in ALL cars are worn out by 197k miles. The electric motor brushes wear out and when that happens the pump fails. 

Almost all cars with a crank sensor code is NOT a crank sensor. All the computer knows is that the crank sensor is not reading the crank and therefore the computer 'thinks' that the sensor is faulty. Many cars do not watch the fuel pressure and therefore the computer does not know, there is no fuel pressure. So yeah, classic proof that the computer is helping you with why the engine is stalling, but is not telling you that the part is bad. That is what diagnosis suppose to step in.

All my cars get new electric fuel pumps at 180k, I do not wait until they fail. I've been there before, it's not a good thing. I would replace that first no matter what anyone one tell me. The good thing is that it just might, fix your concern too.

The misfire code may be caused by the fuel pump so I would replace that first. If the pump is barely working, the fuel pressure would be low and therefore the right fuel delivery would not be achieved. IF the misfire code does come back with the new pump, I would question the spark plug life [are they new?], coil, cap/wires if the engine has that.


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## Butcher (Jan 31, 2001)

up


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## Vabeachtennis (Aug 27, 2014)

Butcher said:


> up


I took it to a mechanic and he told me it's the Cam sensor................... I guess someone was right that a P0321 code can now be a Cam sensor???


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## Vabeachtennis (Aug 27, 2014)

Vabeachtennis said:


> I took it to a mechanic and he told me it's the Cam sensor................... I guess someone was right that a P0321 code can now be a Cam sensor???


So now a P0321 morphed into a p0345? That code never came up on my scanner. Only the p0321 and p0301 came up.


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## Vabeachtennis (Aug 27, 2014)

Butcher, Thanks for the bump!


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## dasautony (Dec 12, 2008)

Were u able to solve the issue?


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## Vabeachtennis (Aug 27, 2014)

dasautony said:


> Were u able to solve the issue?


Not yet. The mechanic hasn't even given me a quote yet (It's been there since Wednesday morning). If he doesn't give me the quote by Monday, I'm going to pay him for the diagnostic fee, take the car home, buy a genuine Volkswagen G28 crank sensor, install it and go from there. I will definitely keep this thread updated so someone else can learn or get a good idea of what's happening. 

I still don't know how a P0321 suddenly morphed into a a P0342 when I ran the codes every time the car failed................ The "funny" thing is when I told the mechanic about the P0321, he said that "the code showed too". Wouldn't the first test be the crank sensor? Maybe the Bosch one I bought off of Amazon is defective?


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## Vabeachtennis (Aug 27, 2014)

*Update*

I stopped by the mechanic today and he totally forgot about pricing out parts and labor in order to give me a quote. We talked for a minute and I told him that I was going to take my car back. We settled, I started the car and it ran fine. The CEL was on when I started it and sure enough it was the P0321 again! The car will still run fine until it gets to operating temperature for a while.


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## Vabeachtennis (Aug 27, 2014)

Vabeachtennis said:


> I stopped by the mechanic today and he totally forgot about pricing out parts and labor in order to give me a quote. We talked for a minute and I told him that I was going to take my car back. We settled, I started the car and it ran fine. The CEL was on when I started it and sure enough it was the P0321 again! The car will still run fine until it gets to operating temperature for a while.




I finally received the part today, looking to install it in a day or two. I've been starting up the car just to keep the battery good, the CEL light for the P0321 shut off on it's own, instead I had a "low brake Pad" warning light illuminated. I haven't been driving the car anywhere. The re4ason why I'm bringing this up, is that it rained pretty heavily this morning, I'm wondering if I am somehow having an electrical or electronic problem. 

Like I stated before, the Jetta will run well until it gets warmed and then will either shut off or not start and have a P0321 code. One time it did have a misfire code but cleared right up.


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## dasautony (Dec 12, 2008)

Did it resolve the issue?


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## dr.jetta (Aug 9, 2019)

crank sensor


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## Vabeachtennis (Aug 27, 2014)

dasautony said:


> Did it resolve the issue?


My saga continues; I had two separate mechanics (one with a VAG-Com) tell me that it was the cam position sensor, I had the one mechanic install it and he drove it for 5 miles in the heat and the car was fine. I drove it for 28 miles and it was perfect, I was happy, then it happened again at 33 miles! Stalled and had to get towed to the shop, guess what code showed up again. It was the original P0321 when I scanned it with my OBD scanner. 

Now the car has a new crank sensor and a new cam sensor and still stalls. The mechanic is stuck and I'm stuck as well. Does anyone have any suggestions? 

P.S. This time when I tried to start it, the car tried to restart and it sputtered and died. The rpms went up to 3k but it sputtered and died.


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## Vabeachtennis (Aug 27, 2014)

I guess that my next move should be to replace the fuel pump even though it's a few years old? The mechanic is stumped and I am stumped.


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## Vabeachtennis (Aug 27, 2014)

Does anyone know where the wire on the far left goes to? It was a lot hotter than the other wires to the right. Even the copper looks burnt.


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## Vabeachtennis (Aug 27, 2014)

Vabeachtennis said:


> Does anyone know where the wire on the far left goes to? It was a lot hotter than the other wires to the right. Even the copper looks burnt.




https://www.gotaclassaction.com/vol...ction-over-fuse-boxalternator-cable-assembly/


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## Vabeachtennis (Aug 27, 2014)

Here's an interesting take, I don't know if he's correct but it makes sense regarding that second red wire. If it's faulty couldn't that be my stalling issue?


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## Vabeachtennis (Aug 27, 2014)

This video is making some sense and hopefully shedding light on my problem.


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## stiles321 (Apr 25, 2020)

*Update?*

Im having the same issue(p0321), what was the end result?


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