EPC and Emmisions light on

[Gabie55]

Hi

Sorry if i am repeating a thread i am a newbie to your site and hoping you may be able to shed some light!

I am a little gutted, i bought and picked up an 04 cabriolet yesterday 1.6 yesterday. I was happy with test drive, everything A - OK! After leaving the garage, 50miles down the road the EPC light came on then after 80 miles the emmissions light came on. The emissions light has stayed on and the EPC light comes on after 5mins of driving and both stay on. The car has just passed an MOT and had a full service, 2 new front tyres.

Anybody have any ideas how it could have passed and mot, gone thru an mot, passing emmissions then 80 miles later, warnign signs.

Look forward to hearing from anyone
Gabie55

[Crasher]

Hello and welcome to the forum. This should be a simple sensor issue. First of all you need to go to a garage that has fault code reading equipment for a fault code scan of the engines computer. I would expect this to show either a brake light switch, AMM (for Air Mass Meter, often also called a MAF for Mass Air Flow meter or AVM for Air Volume Meter) fault or possibly a coolant temperature sensor problem. These potential faults are no major issue, a brake light switch is about £10 and takes minutes to fit, an AMM is around £70 genuine VW (the ONLY way you should buy one, do not let anyone tell you anything to the contrary) and also take minutes to fit and a coolant temperature switch is also very cheap at around £20 and takes minutes to fit as well. The car will have passed its MOT easily as other sensors on the car have an effect on the emissions and keep these emissions under control whilst the ECU warns the driver of an issue in plenty of time to try and avoid damage to the extremely expensive catalytic converter in the exhaust system plus the standards the cars own system works to are far higher than those of the MOT testing requirements.

[Gabie55]

Thanks for your quick response i will do that. I also got it wrong it is the ESP light that is staying on too, not the EPC. I have tried turning it on and off and resetting it when engine off, not sure if this chages anything you have recommended.

Thanks
Gabie55

[Crasher]

The ESP light can come on for certain engine faults but it means you also need the ABS system scanning for faults as well as the engine. I just hope it isn’t a sensor called a “combi sensor for acceleration and yaw” at fault as they are very expensive at over £450 plus fitting and they are a common failure on the Beetle.

[Gabie55]

Hi i took it for a diagnostic test today, the check engine light was a loose connection to the air temp sensor, if comes on again sensor to be replaced, but fingers crossed ok. As for the ESP light they could not connect to the EPC so taking it to a vw specialist this afternoon, more money!!!

[Crasher]

It is the ABS (brakes) you need scanning for the ESP light, the EPC is the Electronic Performance Control which is part of the engine system.

[Gabie55]

Right thi sis doing my head in as i dont understand!!. Took it to a vw specialist this afternoon, came up with 2 faults:
1) Engine: Intake air temp.sensor (g42); signal to high
2) ABS brakes: component esp front: engine control module
013 - check DTC memory - intermittent.

The air intake sensor had a loose wire that was supposedly fixed this morn but shown up again this afternoon on diadnostic. The emmissions light has went of and stayed off ever since but clearly still showing a fault.
The esp light hasnt resolved at all but comes on after 2-3 miles travelling then stay on until ignition off then process is repeated. A fault has come up on diagnostic.

The garage is proposing to change the air mass meter which will sort out both faults. I dont understand what they have to do with each other and the emmissions light isnt the problem anymore.

Sorry so long winded, very confused:Blush2:
Thanks

[Crasher]

The IAT sensor is in the Air Mass Meter and a fault in the AMM can make the ESP light come on so you need to get a new exchange VW dealer supplied Air Mass Meter which is relatively cheap and very easy to install. Trying to explain to you the load cross check calculation algorithm could take a while so just take my word for it, have a new AMM fitted.

[Gabie55]

Thank you soooo much for your advice. I'll let you know how that goes, its booked in tom.:Blush:

[Gabie55]

That didn't work!! still both lights on, any ideas? tehy are saying either getting into the ECU or see if its a wiring problem, both laborious and sound costly. I now have a problem with the flaps on the car not going down when the hood is raised and the stereo going quiet and then loud! Starting to hate this car after 5 days of owning it. It only has 22000 miles on it!

[Crasher]

Did they give you a fault code report of what codes are on the two ECU’s now they have changed the AMM? Where are you?

[Gabie55]

Hi

I live in bournemouth. Fault codes were exactly the same, have spoken to he garage i bought it from and he has offered to collect car, sort it out and drop it back! As he is in south end on sea.

[Crasher]

Good, get back to me if you need any more help.

[Gabie55]

Thanks will do:Blush: