EPC light, car slows to complete stop mid-drive randomly

[hawk91]

I have a 2007 Audi A4 Quattro 2.0 liter 4cyl Turbo / Automatic (No Modifications). In the last few weeks while I'm driving, I will notice the RPM needle bouncing a bit, usually resulting in me losing 3-5mph for a second or 2 and then the speed gets back up to normal cruising speeds.

My main concern is the EPC light coming on at random times and then my vehicle all of a sudden slows down to a complete stop, mid drive, and I have to put it in park and turn it off for a few seconds then turn it back on and it drives fine from there. This happened to me while I was on the highway the other day going 60mph and it was scary to say the least, fortunately I was able to pull over on the median before the car completely stopped in the middle of the highway.

Ran a scan and a few codes have popped up.
P0343 Camshaft position sensor
P0611 Intake camshaft
P0011 camshaft position - timing over
P0455 EVAP emission system
P0016 camshaft

I've spent hours reading through various topics in the forums and most people say it could be the Engine Speed Sensor but of course I'm not certain.

Any ideas ?

[Jeevan]

Reading your post, you said "After reading for countless hours, I think its a speed sensor" it makes sense that you know nothing about cars as you came up with most irrelevant conclusion. I recommend you too take it to a mechanic.

most likely "HPFP/timing chain/camadjuster/tensioner is f'ed".


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[EvolutionArmory]

P0611 is a fuel injector control module fault for like a power stroke motor or something. Are you sure that’s correct?

As for your other codes, you gotta make sure cam timing is correct and engine timing is correct first. From there if everything is correct you can start diagnosing sensors.

[csevans]

Cam, cam, cam, cam .... and the conclusion was “speed sensor”? I’m not a mechanic ... but I’d be leaning towards a CAM issue.
i’m guessing this is a relatively new car (to you) and it has a spotty service history.
Get off the road, and get to a mechanic before you do something stupid and blow the engine. Find someone who specializes in VW and European cars.
INSIST on a CAM follower replacement. Domestic mechanics look at you funny when you say that.

[EvolutionArmory]

^^^ This.

If you look up all of these codes on Ross Tech wiki except for EVAP fault they all have one thing in common. Every one of them tells you to make sure cam timing is correct by counting links and to make sure engine timing lines up with cam timing. Meaning check timing.

Once you do that then you start checking chain tensioners, cam adjusters, engine control relays that the parts share, sensors and wiring.

They all have common themes and your first step on all of them is to check mechanical timing.


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[Silveravant]

If the EPC light is coming on it sounds like some kind of electrical problem. If the timing is off I don't think it would cause the EPC light to illuminate.

May be more than one fault.

[Theiceman]

okay im going to put a different twist on this ....
camshaft timing rarely brings your car to a stop slowly then you restart it and you are on your way ...
camshaft timing is usually is in reference to the crank position ... and the one thing OBD2 in general does poorly is monitor crank position...
what if .. and just a what if .....

he is losing crank position.. this would throw cam/crank correlation codes.. also we know the crank position sensor failure mode is dieing due to heat... but then will restart when it cools down ...

As mentioned though you do NOT want to play Russian roulette with these codes as they will terminate your engine.
I would get it off the road , pull the covers and validate your static timing ( or have a mechanic do it ) if it all looks good i would look at that crank sensor ... the CAM sensor will not stop your engine.

[hawk91]

Reading your post, you said "After reading for countless hours, I think its a speed sensor" it makes sense that you know nothing about cars as you came up with most irrelevant conclusion. I recommend you too take it to a mechanic.

most likely "HPFP/timing chain/camadjuster/tensioner is f'ed".


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I never said "I think it's a speed sensor" I clearly said, (most people say it could be a speed sensor.) I already stated I was not certain and never came up with a conclusion.

No idea how you blatantly ignored that and made up something completely false that I did not remotely say. I do appreciate the suggestions and I'll look into but honestly no reason for you to be a douche making up things I didn't say.

[hawk91]

P0611 is a fuel injector control module fault for like a power stroke motor or something. Are you sure that’s correct?

As for your other codes, you gotta make sure cam timing is correct and engine timing is correct first. From there if everything is correct you can start diagnosing sensors.

The code I got was a p0016 not a p0611. And thanks I'll double check both of those asap before diag

[EvolutionArmory]

okay im going to put a different twist on this ....
camshaft timing rarely brings your car to a stop slowly then you restart it and you are on your way ...
camshaft timing is usually is in reference to the crank position ... and the one thing OBD2 in general does poorly is monitor crank position...
what if .. and just a what if .....

he is losing crank position.. this would throw cam/crank correlation codes.. also we know the crank position sensor failure mode is dieing due to heat... but then will restart when it cools down ...

As mentioned though you do NOT want to play Russian roulette with these codes as they will terminate your engine.
I would get it off the road , pull the covers and validate your static timing ( or have a mechanic do it ) if it all looks good i would look at that crank sensor ... the CAM sensor will not stop your engine.

The car runs with the cam sensor unplugged, right?




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[hawk91]

Cam, cam, cam, cam .... and the conclusion was “speed sensor”? I’m not a mechanic ... but I’d be leaning towards a CAM issue.
i’m guessing this is a relatively new car (to you) and it has a spotty service history.
Get off the road, and get to a mechanic before you do something stupid and blow the engine. Find someone who specializes in VW and European cars.
INSIST on a CAM follower replacement. Domestic mechanics look at you funny when you say that.

Yeah that's why I wasn't understand some people saying it was a speed sensor with all the cam issues popping up. & yeah service was spotty before I owned. Thanks for the feedback & suggestion Ive definitely had that experience with domestic mechanics recently

[hawk91]

If the EPC light is coming on it sounds like some kind of electrical problem. If the timing is off I don't think it would cause the EPC light to illuminate.

May be more than one fault.

Yeah that's what I was thinking as well

[EvolutionArmory]

If the EPC light is coming on it sounds like some kind of electrical problem. If the timing is off I don't think it would cause the EPC light to illuminate.

May be more than one fault.

The EPC light is triggered for non emissions related faults. It’s true that the EPC light is usually triggered by something electrical and usually something directly related to the throttle but not always.


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[hawk91]

okay im going to put a different twist on this ....
camshaft timing rarely brings your car to a stop slowly then you restart it and you are on your way ...
camshaft timing is usually is in reference to the crank position ... and the one thing OBD2 in general does poorly is monitor crank position...
what if .. and just a what if .....

he is losing crank position.. this would throw cam/crank correlation codes.. also we know the crank position sensor failure mode is dieing due to heat... but then will restart when it cools down ...

As mentioned though you do NOT want to play Russian roulette with these codes as they will terminate your engine.
I would get it off the road , pull the covers and validate your static timing ( or have a mechanic do it ) if it all looks good i would look at that crank sensor ... the CAM sensor will not stop your engine.

Not gonna take a risk on it as you mentioned. Closest mechanic near me that specializes on VW/european cars is about 35 mins away so hopefully it'll be good to make the trip just won't take any busy roads

[hawk91]

^^^ This.

If you look up all of these codes on Ross Tech wiki except for EVAP fault they all have one thing in common. Every one of them tells you to make sure cam timing is correct by counting links and to make sure engine timing lines up with cam timing. Meaning check timing.

Once you do that then you start checking chain tensioners, cam adjusters, engine control relays that the parts share, sensors and wiring.

They all have common themes and your first step on all of them is to check mechanical timing.


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Thanks I'll double check on that

[Theiceman]

The car runs with the cam sensor unplugged, right?




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yes my car runs with the sensor unplugged, it will throw a code obviously but defaults to base mapping to get you home.

[Theiceman]

busy roads or not busy roads makes no difference, if you have AAA get it towed there ... 35 minutes engine even idling is a lifetime with those codes if you do in fact have a failing tensioner on the belt, missing teeth on the belt, or the tensioner on the chain.

Im normally not a doom and Gloom guy , but this is one set of codes you DO NOT F@#k with.

[csevans]

35min at surface street speeds could be OK - but I'd get it towed. Make an appointment, dont just arrived his garage door.
Let him (using him generically, he could be a she - no judging at all) know the codes and that you will want a cam follower replacement (~$40 plus labor). Sounds painful, but it is a fairly regular maintenance piece in these engines. Some go as far as doing it every oil change (I'm not that anal - mine gets done annually).

The Cam (opens the valves) and the crank (rotational motion of the pistons) are two sides of the same coin, and they have to dance together for your engine to run. If they get out of sync, there can be issues. They should check the belts and the timing while they are diagnosing the problem.

If they are pulling spark plugs and coil packs (likely), and you are unsure when the last time they were replaced might have been - this would also be a good time to upgrade them as well. Get a set of NGK PFR7S8EG plugs, and something like the Bosch coil packs (you can do the coil packs yourself, but unless you have the tools, get the mechanic to set the sparkplugs).

The important thing is to get the car to a baseline, known level of maintenance. The cam follower, belts, timing, spark plugs, and coil packs are all things that *should* have been done as maintenance items along the way, but it you dont know when that was get them done now. Living in Ohio, I am going to bet you'll need a deep cycle battery before winter hits as well.

These cars arent cheap :)

[Jeevan]

Not gonna take a risk on it as you mentioned. Closest mechanic near me that specializes on VW/european cars is about 35 mins away so hopefully it'll be good to make the trip just won't take any busy roads

Labor and parts" you are looking at over 2000 plus tow" for timing chain service. If the cam adjuster is bad, its further 600-700$ deeper. Make sure your pockets are thick. In case you dont know, this car have timing belt and timing chain. If the car has miles over 150k, I would says its not worth it to be fixed by a mech, watch youtube take time and fix it.

Keep this in mind before towing there. Its a rabbit hole, especially the EPC light lol. Last time I got EPC light its was worn HPFP piston. As Other said its electric, fuel, throttle etc but for now this is least of your worries.


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[hawk91]

Appreciate all the feedback from everyone. I'll drop an update tomorrow once the issue/issues are verified

[hawk91]

So went to my mechanic, said he just needs to replace the camshafts & some sensors and nothing else looked bad so that was pretty good news. Nothing close to the $2k someone said I was gonna end up needing to get repaired. Thanks for any suggestions provided.

[Theiceman]

So went to my mechanic, said he just needs to replace the camshafts & some sensors and nothing else looked bad so that was pretty good news. Nothing close to the $2k someone said I was gonna end up needing to get repaired. Thanks for any suggestions provided.

well thats good news .. get you old parts back and show pics.

[Jeevan]

So went to my mechanic, said he just needs to replace the camshafts & some sensors and nothing else looked bad so that was pretty good news. Nothing close to the $2k someone said I was gonna end up needing to get repaired. Thanks for any suggestions provided.

is he replacing camshaft for free lol.

camshaft( just part alone is 600$) replacement> then chain & tensioner> labor

either way, looks like he is honest.



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[esandes]

Why do the camshafts need to be replaced?