Hi peeps, I came across a strange issue with my car today. I wanted to run few tests and observe some live data with the diagnostic while driving. When I connected the diagnostic tool and scanned for error codes before starting driving I got five engine codes together which puzzled me big time. The engine behaves and runs normally, nothing unusual, so I assume this could be related to some harness issue or it is a sign for something that is breaking up and will require attention soon.
I cleared the codes, drove the car, rescan few times, nothing reappeared, however I don’t feel confident that this was a glitch, or something bizarre and it is not pointing to a problem.

The engine is 1.8tfsi petrol, turbo, 160 hp, 2009 Audi A4.

Theses are the error codes: P0118 P2016 P2008 P0343 P0190 - All of them are Intermittent, so maybe the ground wire needs checking?!


I’m attaching few screenshots as well.

Hope someone can point me in the right direction.

TIA

 

"I cleared the codes, drove the car, rescan few times, nothing reappeared, however I don’t feel confident that this was a glitch, or something bizarre and it is not pointing to a problem"
As a programmer, I'm well aware of bugs. This might very well be one. Don't magnify this. Keep on driving and if reappears you can investigate further.

 

Given the ability of the ECU to store codes, the codes may or may not have occurred at the same time since you don't have any time stamp data. Clearing the codes and then re checking for their re appearance is probably the best course of action.

None of your DTCs except p0190 show up in the version of the service manual that I have which covers the later engines so I can't comment on the specifics of the other error codes. In the service manual I have P0190 which has the malfunction criteria "High fuel pressure sensor voltage > 4.8 V"; but, that does not necessarily mean it is a voltage problem. It could be high pressure; but, then I might expect a P0910 so it might be a voltage issue causing that error unless your ECU does not support P0910.

Ground connections can always be an issue; but, having multiple ground issues would be unusual unless those sensors have a common ground point. I don't have the service manual for your car so can't tell. The one thing I have come to learn about Audis is that they are notoriously sensitive to the 12 volt system voltage. Aside from the battery getting decrepit, the B8s have a not uncommon issue with deterioration of the 12v primary wiring inter connecting the alternator - starter - front distribution point so it might be worthwhile checking that.

I don't know whether OBD11 supports logging. If you had VCDS you could set up to log the 12 volt system voltage while you took the car for a spin. If the 12 volt system voltage crashes really low during starting or is doing some funny things while driving around. If the voltage is taking some significant excursions that might tell you that you have a voltage control issue on the charging system that needs investigation. Not unusual on a 15 year old car.

Of course, you could clear the faults and they might never return.

 

First of all, thank you for your input, very informative and helpful! Regarding the cable you are right, few years ago I noticed big difference in the voltage measured on the positive terminal under the windshield vs the one measured directly on the alternator. To fix this I bypassed it, I pulled additional cable (quite thick and good quality one) directly between the positive end of the alternator and the terminal. It works as a charm, so not an issue.



Regarding this suggestion I have to say that few years ago I noticed very strong and significant fluctuations in the voltage when the electrical system was over loaded (many consumers running like headlights, fog lights, heating of the rear windshield, music on, lights in the cabin, aircon on etc…) It was dropping from 13.8-14.0 to 12.5 and back, on equal intervals, like every second or so. I got super suspicious and I bought a new alternator regulator (original from Bosch), but then this thing disappeared so I didn’t replace the regulator, still have it though. I will investigate further and if that’s the case I will replace it. Anyway, I have the new one, the old one is old and already showed bad signs in the past so I might just replace it.

I will post if any updates.

Cheers guys

 

All those codes are devices on the 14-pin connector hanging under the rear of the intake manifold, near the N80 EVAP purge valve. Is that connector loose?

 

I will have a look, great information, thanks!

 

I checked the 14 pin connector as well as the other two. I disconnected them, checked the pins visually (all looked shiny) and connected them back, made sure they clicked properly. There is a reason to check these 3 connectors because a month or so ago I ran some cylinder compression tests and had to disconnect them (to cut the fuel for example) and when SMac770 said the error codes are coming from devices all connected to the same connector it clicked in my mind that could be related. BTW, while checking today I didn’t find anything off around the 14 pin connector, but let see…

With regards to the previous idea related to possible problems with the voltage or the ground wiring - if this was the culprit it would affect multiple devices and I would get much more error codes, but since it affected only these 4-5 devices and they are all connected together with the same connector this definitely tells me the the issue is local, related to wiring or connector. Big thanks to SMac770 who provided the information that all these devices are connected together.

One more thing - while checking today the harness I saw the black wire on the green 3 wire connector lost its entire insulation 😳 attached photo

Any idea what is connected to this connector? This is super weird and very concerning problem. I assume I should expect this thing to continue with other wires over and over again and probably to be going worse.

PS: Found it , it is Connection piece Knock sensor (#29 on the schematics). It is very odd that only the black wire which I’m assuming is the ground one based on its color got peel off, on the other two the insulation looks alright.

 

The knock sensor black wire not being fully insulated all the way to the connector is the same on my car.

As for the codes, they are intermittent, not confirmed. I don't put much effort into intermittents. Clear them and if they don't come back, it's fine. Codes do not self clear rapidly. If you were playing with the 14-pin at some point, then the codes are probably from then. Codes have freeze frame data that says when they occurred. Don't know how you see that data with OBDeleven.

 

Thanks SMac770, I appreciate the info and the advice. Happy new year!