Need Help ECU problem

[vwthunder]

I am having a problem with my car (07 polo gti), was driving it yesterday and the check engine light came on the dash.
I stopped and pulled over and scanned it with my ESC Scan tool and about 7 codes came up P1548, P1433, P1527, P1421, P1289, P1200. Most of them say short to earth.

Disconnected the battery today and when I connected it, all the lights came on the dash, ESP, Power steering, Check engine.
I have no power steering and no idea of what is going on, had a check over things and cant see anything wrong, car starts fine, so i guess not the battery, any ideas ?

I am hoping it isn't a computer problem, should I try to find another computer and swap it over, I dont really want to pay someone $100 a hour to try to work it out as it could take them forever

[h100vw]

Does your tool clear fault codes? If it does clear them and see what comes back.

Gavin

[philthy]

Don't think your car will start if you swap the computer over.. I believe the key is coded to the ECU. (Gavin?)

[h100vw]

That's true, you would need to have the ECU coded to the key and instrument cluster. A job for someone like Jimmy or VW unfortunatly.

Need to clear the codes and check it again, before buying anything.

Gavin

[vwthunder]

Yes my tool clears engine codes, but not the ESP or Power steering ones, even after disconnecting the battery for a while faults are there as soon as i turn the ignition on, the oil light briefly flashes too

[h100vw]

I don't think the faults aren't going to be due to an ECU fault. I don't know anything about your ECS tool as I have a VCDS lead. I wonder if a VCDS lead would give more information.

The ESP could be due to the ABS, as it needs the sensors to detect wheel speeds.

I reckon a more thorough scan would help.

Gavin

[Jmac]

Just watch if the torque load signal is wrong this can switch off the esp, which will bring the light on, done a few A4s and it was the air flow meter that brought the ESP light, not uncommon. Anyway just checked the diagram for the BJX and most of your fault codes are linked, with a common feed, so my 1st check would be fuse 14 in the fusebox. The link also ends up at the Secondary air pump, have done a couple of these, but they normally give prior warning. Havent changed many ECUS really , ones i have have been water damaged lately, or reversed polarity due to incorrect jump starting, they are pretty reliable now. Anyway dont want to rattle on, check the fuse and if you need a diagram give us a yell
Jmac

[Guy_H]

Yes my tool clears engine codes, but not the ESP or Power steering ones, even after disconnecting the battery for a while faults are there as soon as i turn the ignition on, the oil light briefly flashes too

Troy,

your inbox is full!

Sounds like the ECU is losing communication with the Can bus system, now that could be battery / wiring / bad earth / master fuse.

If the car still runs, good news is it shouldnt be the engine ECU!

Let me know if I can help further.

[Jmac]

Simple as this then, if the above has been checked and you are experiencing more than engine stuff, do as Guy says a Can check, but you will need to do this with live data. Block 125 in any of the ECus running can will tell you whats down. All you need in a can network is 1 ecu to be down. I see it like a christmas tree in series, what happens when you pull a bulb out??? the rest go out. Make sense?
See if you can get someone to do a proper live data check and decent scan. Will be something simple but very hard to do internet diagnosis, without the google mechanics steering you the wrong way
Cheers
Jmac

[vwthunder]

Troy,

Sounds like the ECU is losing communication with the Can bus system, now that could be battery / wiring / bad earth / master fuse.

If the car still runs, good news is it shouldnt be the engine ECU!

Thanks, I have been having stereo problems for the last say 3 weeks, keeps turning on and off

I am working flat out till monday and all of my tools are at a mates house, I will get hold of a mulitmeter on Monday and do a few tests

Can the Connects2 Canbus adapter for the headunit have anything to do with it? or was that just the beginning of the whole system going mad

[noone]

Simple check, remove your head unit, check cabling.

[vwthunder]

Took the headunit out. Didn't make a difference. Doh

[pologti18t]

Could it be a failing battery??

[Jmac]

Took the headunit out. Didn't make a difference. Doh

Can check with VCDS mate, block 125

[vwthunder]

Did a scan thanks to johnw, thanks for the use of the cable