EPC Light

[Mouzer23 0]

Hey Guys,

 

So a few days ago I was on the motorway and hit 2 big puddles of water. The car was fine for about 10 mins. It then jerked to which i noticed the EPC and ESP lights come on. I carried on driving as all seemed OK. After a while when I was on a down hill (so foot off the throttle) I saw the EPC light go off but ESP still remaining on. When I again pushed the throttle for a second there was no power and then jerked and the power came back in and the EPC light returned.

 

When i came off the motorway the car would not idle and die. If i start the car and rev it up (above 3000) i can drive it. Its strange as the problem is intermittent. Yesterday i went to start it. Started fine,idled, drove fine (with EPC light on) and after 15min of driving the EPC light would go off and the jerking would start.

 

Today i start it, the EPC light goes off after 3 secs and the car dies. I need to take the car to an auto electrician but any help from you guys would be awesome!!

 

2003

MK4 V6 4Motion

 

 

Shap! 

[Nex 17]

I would say the water either got to your coilpack or your maf buddy. the quickest way to find out if it is either of these 2 bits would be to take each of them off (both really easy) and give them a good drying out in the house. Dry off the connectors, hook them back up and see if the problem is gone.

 

also if you can get it scanned with vagcom would tell you pretty quick whats what

Edited December 30, 2013 by Nex

[Mouzer23 0]

Thanks Nex,

 

So far i removed all the coil packs, removed the piping between the air cleaner and the throttle, disconnected all leads cleaned then sprayed with WD40 and left the dry for 2 hours. ( i was sure this would fix the problem) but i did not.

I have replaced the MFA before in this car 4 years ago. do you think the MFA would work fine above 3000 RPM and give issues below that? what i also don't under stand is that when the EPC light is on the car starts runs and idles fine. if it was a coil-pack  or the MFA surely it would be a permanent  problem.

 

Thanks again for any help. 

[Nex 17]

Unfortunately not, the problems tend to be intermittent for a while in some cases before they become a permanent issue.

 

I take it you have the individual coilpacks then and not the block? 

 

Yeah MAF could still be the issue, l had one that did something similar before so it is always worth checking. If there is someone with a 4mo close that you could ask just to try theirs on your car to see if that sorts it, if it doesnt then you know it is something else.

 

But to be honest your best bet (and the fastest) is to look for the vagcom people willing to help part of the forum to see if there is someone in your area that could give it a scan. this would tell you exactly whats up and would save some trial and error

[shawy 3]

Got a 4 motion maf here for sale excelent condition. Also anything else u may need engine wise ...

[RBPE 198]

There are two correction factor maps for the MAF based on combustion chamber pressure and cam timing with throttle angle/rpm axis - just wondering if there was a touch of hydro-locking and the ecu has been unable to properly compensate?

[craggsy 91]

Need to get it scanned as could be anything

[RBPE 198]

Yeah have it scanned by someone if you don't know what you are doing.

 

I would think it is running a diagnostic through error path routines and as such, tripping it up.

On the R32 and V6 4motion they should be located in the same place.

 

I've highlighted the areas in red on the hex dump and in the binary except MIL Codeword is just off the screen after the other two EPC lamp codes; 10790/10791/10792 for diagnostics but it could be other bits that are triggering it.

 

Edited March 19, 2015 by RBPE

[RBPE 198]

P.S. On the oem maps - 10790 is 2 seconds and 10791 is 51 seconds if that relates to what your car is doing.