Fabia 1.6 TDi Elegance - Exhaust Control Unit Fault

[PassatNoMore]

My car has done just over 5k and on holiday last week the ECU lamp came on - no text in Vehicle Status panel. No noticable effect on performance and MPG seems good. I also had a flashing glow plug warning for about 20 minutes whilst driving home down the A9. It disappeared after restarting the car following a coffee break.

I booked in to Chathams for today but ECU lamp went off on the way there! Maybe like goinig to the doc and your symptoms disappear just before the appointment ?

Anyway Chathams said the fault may or may not be stored so might not show up on diagnostics. I decided against leaving the car with them and said I'd re-book it if the fault came back.

I'll keep you posted on progress.

[Mike Wrightson]

Your DPF needed a regen desperately. When the glow plug light starts flashing along with the ECU light, that is the last chance for it to regen before it goes to limp mode. If you had not driven those 20mins your dealer would now be doing a scary forced regen for you.

How much mileage do you do, and what sort of trips?

[jrw]

You would have a DPF light on if the DPF needed a regen surely?

[PassatNoMore]

No DPF lamp at all and I think regen is working ok - burning / rubbery smell was evident a couple of days after the ECU lamp came on

I'm doing a reasonable town and long distance mix , especiialy after driving to holiday destination.

[Mike Wrightson]

OK, I'm confused, you describe it as an Exhaust Control Unit? Do you mean the emissions light or was it the Engine Management light? Either way, the flashing glow plug light coming up too is not a good sign, the only time I've seen that was with my brothers car after the DPF/emissions light comes on. If the regen that follows isn't enough, the glowplug starts flashing. If it still can't it goes to limp mode.

I'd say it's worth getting the car to them to read fault codes anyway.

[PassatNoMore]

Wording in handbook for the warning light is "Control System for Exhaust" It advises that the engine management system would switch to an emergency programme so that the car could be driven ... in a gentler style. What would that feel like because when the lamp came on there was no difference in the feel or performance ?

When I talked to Chathams initially, they didn't suggest a link with the DPF. In fact, I mentioned a burning smell that my wife had advised was very intermittant. The service guy explained the regen process to me (I must have not been paying full attention when I first took delivery).

Anyway, I'll take your advice and get it booked in asap.

[Mike Wrightson]

You would know if it was in limp mode. You'd not be able to go past 50mph and power would be slashed.

[PassatNoMore]

Well for definite it's not been in limp mode. Sods Law but the fault lamp came on again tonight and I had flashing glow plug for about 20 seconds. I'm hoping that it's a problem with the monitoring system components rather than a real fault.

[aak]

My wife's car had a similar problem

A few weeks ago - albeit without the flashing glow plug symbol - only the exhaust control warning lamp - amber coloured engine block! No limp mode. Skoda assist diagnosed a faulty exhaust gas sensor ( number 3 I think ). Sensor replaced by Skoda assist and an ECU update downloaded. Car's been fine ever since.

[PassatNoMore]

Here's hoping mine's the same

[RGKTSi]

My father in law had the same issue with his Fabia 105TDi. As AAK said, faulty exhaust gas sensor, simply replaced by dealership under warranty and ECU updated. All fine now. I had already diagnosed the issue with VCDS. Strangely it made no difference to the running of the car.

[delta925]

I had the orange glow plug night start flashing just as I got home tonight. The DPF light was not on and from the smell a regen was taking place. Last Thursday I did two 120mile continuous journeys on motorway & dual carriageway and the previous regen was only last Tuesday so only about 300miles ago in total.

My normal regen interval is around 300 miles but my basic journeys are 11 miles to/from work and short weekend trips. With the long trips I didn't expect another regen so soon.

I restarted the car briefly and the light was off. Time will tell if it happens again. At least I know Skoda Assist can replace the exhaust gas sensor if this is the cause without a e time taken with a trip to the dealer.

[faither]

Sorry for a daft question but what's a "regen"?

[Mike Wrightson]

New diesels have a particulate filter or DPF, this collects the soot from the exhaust. The DPF will periodically command the engine to increase the exhaust temperature so the the soot is burned off and turned into a much smaller quantity of ash, this is a regeneration cycle, or "regen"

[faither]

Thanks Mike - it's obviously something normal then! Does this continue to happen - just got a Fabia 1.6 TDR with 11k on clock.

[Mike Wrightson]

Yes, it will happen at fairly regular intervals. If you do short trips a lot it will happen more often. Have a look in the handbook and it'll tell you what you need to know.

[seboni121]

Run it on the best possible fuel something like vpower from shell, it will burn better less soot therefore less chance of blockage

[delta925]

Yesterday I had no warning lights but straight away this morning the orange Emission Control System light came on. The car drove normally and revved over 3000rpm so definitely not in limp mode.

Once at work I called Skoda Assist. Since I was not stuck at the roadside initially they said a technician would be with me by 3pm. However about 30 minutes later the called to say a technician would arrive in about 20 minutes. Actually he arrived in about 15 minutes.

He ran a diagnostic check which showed the second temperate sensor in the exhaust system was reading 180C when the first was reading 16C and the third 19C. Once he had uploaded all the results to the HQ system he was given authorisation to change the sensor. He had one on the van to fit and within an hour from arriving he was finished.

All fine as under warranty but since these sensors are carried on the van I wonder how regularly they fail and what the replacement cost would be once out of warranty.

Also if after 3 years you join any breakdown service other than Skoda Assist would they have been able to diagnose the sensor and replace it or would they simply take you and the car to a dealer.

[jrw]

Also if after 3 years you join any breakdown service other than Skoda Assist would they have been able to diagnose the sensor and replace it or would they simply take you and the car to a dealer.

Thats the great thing about Skoda Assistance - Free Diagnostics and labour outside of warranty and you just pay for the part.

[PassatNoMore]

My car has the same daignosis as above - faulty sensor and will be replaced once the part comes into stock. Lamp sometimes goes off. Flashing glow plug indicator occasionaly - usually after about half an hour so maybe temperature related. Car driving fine and good MPG.

[PassatNoMore]

Exhaust gas temperature sensor replaced on 9 July - all fine ever since.

[delta925]

Almost 4 years later I potentially have the same issue again.

Just as before I did a 110 mile motorway / dual-carriageway run then a couple of local journeys then the 110 mile return.
No more than 20 miles into the return the orange glow plug light started flashing but fortunately without limp mode. It stayed flashing for the next 90 miles. I wasn't going to stop and switch off while still running OK but slowed on hills rather than giving much more throttle.

When I got home I switched off and restarted. The lamp was off. I went for a quick 4 mile run including uphill dual-carriageway and gave it some welly. The lamp stayed off.

Today on my two 11 mile trips to/from work again the lamp stayed off. I was ready to call Skoda Assist if it came on.

 

At least now I am back with Skoda Assist after nearly two years stuck with standard RAC service, which fortunately I did not need, when VAG moved Assist to the AA but refused to transfer those who paid to extend the inclusive 3 year support.

The next few days and / or the next regen trigger from the ECU will probably tell if just a glitch, a real problem or a faulty/failing sensor. Unless a change in circumstances involving a much higher annual mileage my future cars will be petrol.

Watch this space.
 

[delta925]

Well two weeks have passed and the glow plug fault indicator has not come on again. My journeys have only been my 11 mile each way commute and local.

 

Four days ago a regen was initiated and apparently ran correctly. It was not ideal timing as split into three. It started on the way home then continued the next day on a 4 mile run and completed before the end of an 8 mile run an hour later. I normally keep in lower gears as necessary so the revs are not under 1600 but specifically tried to keep them up towards and over 2000 on the second day.

 

Once a few days later I noticed while not fully warm waiting at a junction it didn't seem to drop to tickover properly. One thought was a fly-by-wire throttle issue. I have watched but not seen this again. Just before if not when the indicator started I had been on cruise control so possibly relevant / related?

 

Otherwise all seems fine but without forking out ~£100 to a stealer for a diagnostic check which would presumably show what triggered the indicator I'm left wondering if a glitch or a problem looming which will show on my next long run. Please advise if otherwise but from all I can find out the cheaper diagnostics readers on eBay either do not work with post 2010 cars and/or diesels at all or are very limited in what they can display.

 

One recent thread highlighted EGR valve failure and how expensive it is to replace because so inaccessible due to poor design. Others linked threads show this can happen relatively low mileage, also that for the 4WD even more disassembly is required for access.

 

A service and coolant change is soon due, two tyres before the winter and maybe battery then officially as 5 years although now only just over 37k miles the cambelt despite service book simply saying replace at 210000km (130000miles) with no mention of a time limit.

 

Before spending I'm going to find out the costs of changing to a 3 year old petrol Kia Ceed or even possibly Rio primarily because it will have 4 more years warranty.