:(

My son bought a VRS (54 plate) last April 08 and it started going wrong 6 months later.

It has gone srong 10+ times since then and we have been warned by RAC re unfare usage.

When it goes wrong these are some of the symptoms.

On start up the engine revs and hunts.

Sometimes the warning light comes on.

It normally resets itself after a few hours

Initially it came up with a lambder sensor error (sorry about the spelling)

but has also given throttle box error.

It has been in and out of garage many times but when cleared they can not find a problem.

The throttle box has been changed twice! and reset three times which seems to clear the problem.

I think they are clearing the symptoms and not the problem.

This week it has gone wrong twice. and when I started it this morning it started but the throttle did nothing. I put my foot right down and the engine just reved at around 1000.

Restart and the hunting problem was back.

Please can anyone help.

This is a great car when it works.:thumbdwn:

I think the hunting at startup is usually down to a faulty coolant temperature sensor.

If you can get hold of the fault code it is coming up with and post the fault code on here we'll have something to go on.

Don't know code numbers

RAC had lambder sensor and throttle assembly/box error.

Main dealer has looked at problem and can not help!

Where do I go???

Have a look in the VAG-Com section on here and see if there is a friendly member with VAG-Com near you who will do a scan for a few beers Or failing that you can get VAG fault code scanners off of ebay for about £25.

Did they replace the lambda sensor? If so then there must be another fault coming up apart from the lambda sensor and the throttle body if they've replaced those and it didn't make any difference to it.

Try a search on this Octy I forum for "coolant temperature sensor" and see if any of the symptoms other members mention match yours - they usually replace them with an updated version (it's green I think) which cures the unstable revs after startup.

Lambda sensor was not replaced.

Might be throttle position sensor (pedal one) but like above you need to get it scanned to find out for sure. If they replaced the throttle Body did they reset it properly?

Last time the throtle box was reset the fault cleared for nearly 2 months.

But the problem still comes back

Difficult to help without fault codes. As has already been said, maybe a local memeber can hook you up with a free check. Where are you based? Or, you can get a cable from ebay for about £14 (provided you have a laptop).

iep

Based in Plymouth UK

Try checking and cleaning the Exhaust Gas Recirculation (EGR) Valve. It could give you these sort of problems if it was stuck open, and no diagnostic equipment would necessarily recognise that as a fault.

VCDS and others are brilliant tools, but they cannot directly measure anything mechanical, and therefore whatever faults are presented cannot be relied upon as absolute gospel. If in this case the EGR Valve was stuck the ECM would not register it as a fault unless it had moved outside of its programmed parameters.......

I had a non-stop problem with that where a TB alignment would seems to do it for a while and then it'd come back. I eventually paid for a bit of extra diagnostic time at a main dealer on top of a service and they said that a readiness code was missing from the ECU and that they'd reset it. No idea what that means, but it's been great since

*frantically prodding the desk*

thanks inter may be the problem but it seems the dealeres are hiding behind the computer.

Anyway problem there all the time now

EMS codes 17972,17579,17950,17705,16514 and 16684 found by RAC

Also P0130 o2 sensor cirtuit mulfunction

and

P0300 Random multiple sensor misfire

and lambda sensor reading 0volts

These were the faults we had in October I think

I think you may have a problem with the wiring between the TB and ECU. Check for loose wires in the connector first.

I notice from the codes that a TB alignment was attempted but failed.

It could also be faulty potentiometers in the TB.

If you are really unlucky it could be the ECU itself (hopefully the lambda sensor is bad. Like the TB, it gets its power from the ECU and this could indicate a fault in the ECU).

It is in garage, again, at moment and I await their responce!

Thanks for help guys. I have ordered a lead off of that auction site and await its delivery.

O2 sensor error and random mis-fire could be related.

If the coil packs (one or more) are gone or going then this would allow unburned fuel through the system and could cause problems with the o2 sensor.

Worth taking the coil packs out, checking their condition or replacing all 4 IMHO as they are known to go.

Another option is relay 109, which used to cause dervs to go mad randomly. IIRC this controls power distribution to many systems so worth replacing too if the VRS has it as it's a cheap part.

More info on this car. I believe it has had TWO throttle bodies replaced by the main dealer and every time you basic set the throttle body the car runs fine for a long period of time. Also they haven't mentioned the brake pedal goes very hard as if you have no servo assistance. The car in now in my garage on my ramp for repair and thanks to the RAC I have SEVENTEEN fault codes in it as they have randomly unplugged all injectors and coil packs. I believe the car is running on the latest set of ignition coils available from Skoda. As the tech working on this car I would llike to mention there is no way to reproduce this this fault and it only happens every couple of months and most times by the time we see it it's running fine. Tomorrow will be the first time I'm getting more involved with the car and a note we are not a main dealer but a independent garage repairing all makes and models.

I'd suggest making a note of all the fault codes, clearing them all and driving the car and rescanning it to see if anything appears.

As i said in my last post I don't know if the petrol cars have a relay 109 to control power to the ECU but it's well worth a look.

More details here:

Relay 109 - Main Power Supply Fuse - TDIClub Forums

Relay 109 also existed on the Golf mk3 VR6 and was known to cause all manner of issues there too. Always worth checking and can be borrowed from any other VAG car to test with so you don't have to fork out £20.

iep

I had a similar sounding fault, engine hunting on idle, intermittantly dropping into limp mode. There was no consistancy to the faults, even when scanning on VAGcom

I finally discovered water in the connector for the engine position sensor and other connectors. Dried them with compressed air and filled with di-electric greese and I have (touch wood) not had any issues since.

This is a simple thing to check.

thanks inter may be the problem but it seems the dealeres are hiding behind the computer.

Anyway problem there all the time now

EMS codes 17972,17579,17950,17705,16514 and 16684 found by RAC

Also P0130 o2 sensor cirtuit mulfunction

and

P0300 Random multiple sensor misfire

and lambda sensor reading 0volts

These were the faults we had in October I think

Just a thought .......http://briskoda.net/octavia-i/fault-codes-17705-17545-a/7798/4/#post1792250

As you're getting the 17705 code. And its said that your brake pedal goes hard

Car going back in to garage!

All the leads had been checked and TB reset.

Lasted for 1 day before it went wrong again!!!

What a LEMON!

Intermittent grounding issue? Can cause all manner of chaos.

iep

My last post was useless since it included no detail or reasoning (late at nigth and tired).

The only reason I mention an intermittent grounding issues is that my mates clio (fair enough not VAG) lost it's solid GND ground strap between the engine and the chasis. The result was a huge colleciton of random behaviours (and about 20 odd fault codes). As soon as the GND connection becaomes flaky, every other system in the car will start to behave erratically.

It's an easy check for a mechanic to make so might be worth mentioning.

Cheers,

iep

The majority sounds electrical to me. As above check the ECU power supply relay, also check the alternator output. The Octavias have a habit of the main wire from the alternaor to the battery developing a high resistance at the battery end.

With the start up engine hunting problem from cold, the code suggests that the first lambda probe needs replacing, they require heating from cold to work with a cold engine.

The majority sounds electrical to me. As above check the ECU power supply relay, also check the alternator output. The Octavias have a habit of the main wire from the alternaor to the battery developing a high resistance at the battery end.

With the start up engine hunting problem from cold, the code suggests that the first lambda probe needs replacing, they require heating from cold to work with a cold engine.

SO if the alternator output is low then it will not heat properly?