Dashboard light, limp mode and struggling to start, can anyone help?

[quattrojim]

Hello, as mentionned above, was driving and then noticed a light had come on the dash, the handbook says its Diagnosis/Excess of pollution, i then noticed a lack of power on the drive home, i assume this would be limp mode. and when i got home i tried to start the car again and it wouldn't start, just turning over, i turned ignition off and tried again and it worked

i have read that after some problems and dash lights coming on the car will go into limp mode as a safety feature, is that right? has anyone had problems with this light coming on?

but the problem starting the car, could this be realted or a seperate problem? i did have issues about 2 months ago, the car was struggling to start over the space of about a week and then it died completely, the AA said the battery had a dead cell and i replaced the battery and been fine ever since.

until about 2 weeks ago, i did a 3 hour journey, turned the engine off and then had to move the car again and it sruggled to start, the next morning it started fine. haven't had another problem until this morning.

can anyone give me some advice please?

 

[quattrojim]

i have just read another thread that was titled struggling to start when hot, could this be the problem with mine as both times it has had problems starting was after journeys when it would have been hot?

 

[Muttley]

You drive an Audi A4. Bit cheeky, asking for help on the Seat forum?? ;-)

The "Diagnosis/Excess of pollution" light is also referred to as the "Check Engine Light" (CEL) - it basically means that the ECU has detected a problem and wants you to take it to a dealer who will hook it up to a diagnostic computer read the fault codes stored in the Engine Control Unit (ECU), then suck his teeth and give you an estimate for fixing the problem.

The ECU will revert to one of several "limp home modes" if it detects a problem with the signals from the sensors it uses to keep track of the engine's activity: things like coolant temperature, engine rotational speed, manifold pressure; parameters it needs in order to calculate the correct injection timing and quantities to deliver the power reqested by the throttle pedal.

The diagnostic kit is very good. There is an equivalent, called VAG-com, that can be run on a laptop, using a proprietary cable to connect to the diagnostic port on your car. This allows you to read the fault codes yourself. A post in the VAG-com section of this forum might find someone local to you who has VAG-com and is willing to meet you and do a diagnostic analysis for you.

 

[quattrojim]

hello, cheers for the reply, just to clear up though i did sign up ages ago when i had an A4, and now i have an LCR i just forgot to change the info on my profile.

http://www.seatcupra.net/forums/showthread.php?t=211067

I did figure out the bit about the Vag com and i will be getting it checked this week but just wondered if anyone might have more of an explanation of the problem?

 

[quattrojim]

when i started the car this morning it started fine, light on dash has gone off and all the power is back, is this normal that a fault could have come up and then cleared itself again?