Hi All 

 

I was hoping someone could point me in the right direction. My old Fabia is throwning up a check engine light on almost every journey (often from the moment the key is turned, sometimes a couple of miles into the first drive of the day) and going into limp mode frequently. 

 

Apart from that all seems well. When not in limp the car is running great. When it goes into limp a quick engine reset and it is fine, but after anything from 5 seconds to 10 mins it's back into limp. 

 

I can't see much of a pattern in terms of what is causing it. There doesn't seem to be any common environmental or driving style triggers other than it only does it when the engine isn't under load, i.e. when static or down around 1000 - 2000 RPM. So on the motorway at 60mph in 5th it's happening every couple of minutes or more. If it's being revved hard it'll drive all day with no issues, but I can't be going around like that. 

 

Fault codes - 

 

19461 - Power Stage, High Heat; Short Circuit to B+, Intermittent.

 

19459 - Power Stage, Low Heat; Short Circuit to B+, Intermittent.

 

17932 - Fuel Pump Relay, Short Circuit to B+ or Ground, Intermittent. 

 

The garage have told me that they suspect those codes are not the cause of the problem and they suspect a sticky sensor on the turbo, they've suggested I give it a good thrashing and report back before considering a replacement turbo. 

 

It's had a good few thrashings and there has been no change. Before it goes back and I start blindly throwing money at the problem, anyone seen this before or got any ideas? 

 

Car details - 

2005 Skoda Fabia Elegance Estate

1.9 TDI PD 100

VIN No. TMBGS46Y454327014

170k Miles

 

Any suggestions would be gratefully received. 

 

Thanks

 

10 hours ago, TriggersFabia said:

they suspect a sticky sensor on the turbo

Likewise. Look on the Octavia guides forum for "Mr Muscle fix".

25 minutes ago, KenONeill said:

Likewise. Look on the Octavia guides forum for "Mr Muscle fix".

 

I'll take a look. Thank you. 

Thanks for the pointer @KenONeill

 

The comments on the Mr Muscle treatment seem to indicate that this works great to treat the car going into limp when high revs are applied. 

 

Mine has the opposite problem, it goes into limp at low RPM. It loves high RPM.

 

I couldn't see anyone there using that method to treat problems at low RPM, and this doesn't tally in my mind with the sensor getting stick through lack of travel as this is obviously more likely to effect the upper part of it's range of movement than the bottom.

 

I spoke to the garage this morning and pointed out that the problem only manifests itself at low RPM. That caused the mechanic to rethink the cause of issue and refer it to a colleague with more auto electrical knowledge to diagnose. 

 

Any ideas still welcome, and I'll keep this thread updated either way. 

http://wiki.ross-tech.com/wiki/index.php/17932/P1524/005412

 

You need to fix this, it could be causing the problems.

Hi All, 

 

Now solved, it was a partial ECU failure caused by water making its way into the unit. I sent the ECU off to be cloned and the replacement ECU I got back fixed the problem instantly. It's been going strong for two weeks now with no further issues.

 

Thanks for the help/suggestions. I hope this helps someone with a similar issue in future. 

 

I wonder if someone had previously opened it up for some reason, and failed to re-seal it adequately? 

Any pics of where the water got in?

Good on you for feeding back with the fix.  

I haven't opened it up, I noticed condensation droplets around the connector pins after I unplugged it and so I set in on the kitchen side with the connectors facing down. I came back an hour later to find a teaspoon of water underneath them. That was enough to satisfy any doubt. 

 

The unit doesn't appear to have been opened at any point (Only my father and I have owned the car from new so realistically we'd know if it had been disassembled previously). I think the seal just broken down over the last 15 years/170k and finally gave way. 

 

It was a relatively cheap fix at £225. I just hope the new one (which is second hand) holds out for a few years. 

 

 

Ignore that if you saw what I just posted, ECU mounts too high up for that to be an issue, I think.

Edited 20 August, 20214 yr by Wino

8 minutes ago, Wino said:

Ignore that if you saw what I just posted, ECU mounts too high up for that to be an issue, I think.

 

Yeah I think my ECU is safe from that.

 

The engine bay is often full of condensation if you open it up cold, I.e on a foggy morning before starting. I assume it was just a build up of atmospheric water from the temperature fluctuations inside the ECU rather than a specific leak.

 

Thanks for the thought though. 

 

I guess the water may have got in via the connector seals, as opposed to the case perimeter seal? 

You know you want to open it up for a looksee...?  

 

Any corrosion damage to the loom connectors' crimp inserts? (May be able to correlate it with specific pins/wires on the ECU).

 

 I've once heard of coolant water getting up along coolant temperature sensor wiring, bizarrely, following internal failure of the coolant sensor. Wicked along within the wire insulation layer all the way to the innards of the ECU connector. 

I've read about the coolant sensor wicking problem too, but supposedly it only affects the early sensors mounted at a downward angle as opposed to the revised 90 degree version like mine has. 

 

And no. It's finally working right after 3 months, 4 confused mechanics and many headaches, I'm not going to go poking about anymore until she makes me. It's been an ordeal and frankly all the time she's happy I'm not going to rock the boat. Besides she's already moved on and today has given me a sticky handbrake actuator arm to contend with 

 

 

Oh dear, sorry it's been such an ordeal.  

'Hatboy Harvey' recently put out a youtube video about disc handbrake stuff on mk! Fabia.

I haven't watched it yet, but his stuff is usually pretty solid sense, and well filmed and described. 

 

I just watched it. That's exactly what I needed. Bloomin marvellous. Thanks.