Hi All,

 

My 2006 Fabia 1.2 HTP recently developed a hole in flexible exhaust pipe. 

 

The car continued to loose performance before I could get it into a garage and engine light came on and car went into limp mode limiting revs to 3000rpm and speed to 50 mph.

 

The exhaust is now fixed but the engine light and rev situation is still the same, acceleration is completely flat.

 

Any ideas what the root cause could be.

 

Its booked back in to the garage on Friday but I'd prefer to resolve myself.

 

Thanks in advance

You need to know what fault(s) is putting the warning light on.  You can buy handheld scan tools that will tell you fault codes for not much cash, e.g. https://www.amazon.co.uk/U281-OBD-2-CAN-BUS-SCANNER-SKODA/dp/B001C9V89A/ref=sr_1_1?ie=UTF8&qid=1536740561&sr=8-1&keywords=u281

One possibility is that the after-cat lambda sensor (or its wiring) has been damaged during the exhaust section changeover (it is mounted in the front of that section).  Scan would show codes relating to this, if it is the case.  It could just as easily be unrelated to the exhaust situation. Guessing can be expensive.

What's your approx. location?

@Gypolo - As Wino says above; also fixing the problem does not always automatically cancel a fault code, and the CEL fault and exhaust problem may only be coincidentally related.

36 minutes ago, Wino said:

You need to know what fault(s) is putting the warning light on.  You can buy handheld scan tools that will tell you fault codes for not much cash, e.g. https://www.amazon.co.uk/U281-OBD-2-CAN-BUS-SCANNER-SKODA/dp/B001C9V89A/ref=sr_1_1?ie=UTF8&qid=1536740561&sr=8-1&keywords=u281

One possibility is that the after-cat lambda sensor (or its wiring) has been damaged during the exhaust section changeover (it is mounted in the front of that section).  Scan would show codes relating to this, if it is the case.  It could just as easily be unrelated to the exhaust situation. Guessing can be expensive.

What's your approx. location?

 

 

I'm in Birmingham.

 

Just called the garage and they read two errors - camshaft sensor and manifold pressure sensor.

 

Going to have a look now and see what I find.

Just reset the ECU, it's got stuck in limp mode after the exhaust emissions fault. Surprised the garage didn't do this when they fixed it.

19 minutes ago, sepulchrave said:

Just reset the ECU, it's got stuck in limp mode after the exhaust emissions fault. Surprised the garage didn't do this when they fixed it.

Ive taken out, inspected and cleaned the camshaft sensor and the MAP sensor.

 

Just resetting the ECU now.

 

I'll update in an hour or so...

 

Thanks 

45 minutes ago, sepulchrave said:

Just reset the ECU, it's got stuck in limp mode after the exhaust emissions fault. Surprised the garage didn't do this when they fixed it.

I cant seem to reset the ECU. I tried disconnecting the battery yesterday for half an hour and that didn't do it. 

 

I just tried disconnecting the battery and connecting both terminals together for half an hour but that didn't work either. 

 

Any recommendations?

I seem to remember that there isnt a permanent 12V feed to these ECUs, so discoing the battery has no more effect than switching off ignition. If you know or can find your engine code I can look up and confirm.

BMD or BME?

 

1 hour ago, Wino said:

I seem to remember that there isnt a permanent 12V feed to these ECUs, so discoing the battery has no more effect than switching off ignition. If you know or can find your engine code I can look up and confirm.

BMD or BME?

 

unfortunately boot sticker is illegible and my docs are all at home so will have to wait till I finish work.

 

I've tried ECU reset several times so looks like you are right about the 12v feed.

 

Am I right in assuming there is no egr on the 1.2 HTP as I cant find one anywhere?

 

At this stage I'm thinking the MAP sensor is at fault, causing a knock on reading on the cam sensor with the revs going awol due to the limp mode.

 

When I took the car back to garage yesterday he did diagnostics and reset faults (is this the same as ECU reset?). As soon as I drove off the engine light returned so am I right in concluding that the fault is still ongoing?

5 minutes ago, Gypolo said:

Am I right in assuming there is no egr on the 1.2 HTP as I cant find one anywhere?

 

Depends...Never on the 6-valve engines. (Easiest way to tell is colour of the HTP lettering on the back of the car, all black letters = 6-valve; Red 'P' = 12-valve).

On the 12-valve engines, code AZQ always had an EGR valve (front of engine just next to exhaust manifold). Early BME codes still used an EGR valve ( up to mid 2005 production rings a bell) but then didn't after that.

 

MAP sensor fault code could be caused by an air leak, always good to check the brake servo vacuum line on these, they split where the rigid black plastic hose goes over the hose barbs in four places.

I have a vague recollection of the combination of cam sensor code and MAP code possibly pointing at chain jump issues?

 

The exact fault code numbers would be useful.

Clearing fault codes may or may not be the same as an ECU reset, I don't really know.

11 minutes ago, Gypolo said:

am I right in concluding that the fault is still ongoing?

Yep.

 

the P is red so 12-valve.

 

Post 2005 model. I can see the old mounts on block where egr would have been fitted previously but these are all blocked off unless they have buried it somewhere else Its a safe bet it doesn't have one.

 

The servo vacuum line was indeed knackered on inspection this morning so I've taped it up for now (still showing engine light). picking up a replacement on way home.

 

I'll take a look into the chain jump theory now.

 

Thanks for you help with this Wino.

 

If I cant remedy the issue I'll be sure to get exact fault codes from garage on Friday.

 

There's some info on DIYing a chain timing check on the AZQ engine, (which will be the same on BME I'm sure) in this thread of mine from yesteryear; in the post dated 6th May 2012.

 

48 minutes ago, Wino said:

There's some info on DIYing a chain timing check on the AZQ engine, (which will be the same on BME I'm sure) in this thread of mine from yesteryear; in the post dated 6th May 2012.

 

Ok great thank you I’ll take a look as soon as I’ve figured out the latest surprise.

 

so I’ve just drove home and my brakes are now rock solid and virtually unresponsive.

 

The vacuum hose which you mentioned previously had been shot for a long time by the looks of it, all 4 joints were split badly.

 

Now the hose is repaired the brakes are virtually seized.

 

Have you seen any threads related to this and how to fix? 

 

when I bought the car it had brake issues and I had to replace the rear Cylinder and bleed system. It’s obvious now that the vacuum hose was also at fault but at the time I just assumed the brakes were crap 

Bloody hell, that's not very lucky!

I suppose in the very short term you could 'unfix' at least one joint of the servo hose and see if that helps unseize things. A bit of a struggle for my brain to explain this.

Hopefully someone with more brake experience will be able to offer advice on what's likely to have happened there.

I can only think that the servo has seized through lack of use and is maintaining brake pressure, try pulling the brake pedal up with your foot to see if it releases, if so you can 'work' it so it doesn't stick.

 

The vacuum leaks explain the MAP sensor error but not the cam position sensor error.

 

It sounds like your car is in a parlous state due to a complete lack of basic maintenance during its life.

49 minutes ago, sepulchrave said:

I can only think that the servo has seized through lack of use and is maintaining brake pressure, try pulling the brake pedal up with your foot to see if it releases, if so you can 'work' it so it doesn't stick.

 

The vacuum leaks explain the MAP sensor error but not the cam position sensor error.

 

It sounds like your car is in a parlous state due to a complete lack of basic maintenance during its life.

It was a cat c when I bought it so thought it hadn’t had the best of lives, but unfortunately it was all that I could afford.

 

there is no upward movement whatsoever in the pedal but will try releasing the servo in the morning.

 

if I hadn’t just replaced the clutch and exhaust I would consider getting rid but for now I will persist 

Is there a non-return valve on the servo pipe ? Is there any chance it could be on backwards ? That would make the brakes very poor indeed.

9 hours ago, maccy said:

Is there a non-return valve on the servo pipe ? Is there any chance it could be on backwards ? That would make the brakes very poor indeed.

Maccy, Turns out there was a blockage in the old knackered hose, once replaced the brakes now work better than ever.

 

17 hours ago, Wino said:

There's some info on DIYing a chain timing check on the AZQ engine, (which will be the same on BME I'm sure) in this thread of mine from yesteryear; in the post dated 6th May 2012.

 

Wino, Just checked the cam end slots and they are both aligned so timing looks ok. Engine sounds fine and idles as it should. Running out of options to check myself.

 

Another thing, the clutch was replaced a couple of months back. Could this have caused any problems?

7 minutes ago, Gypolo said:

Running out of options to check myself.

So is the plan to take it back to the garage tomorrow, or have you got a scan tool coming?

Maybe look to see if there's a member with VCDS near you: https://www.briskoda.net/forums/topic/262215-list-of-vcds-owners-previously-known-as-vag-com-vcp-owners/?tab=comments#comment-3091029

10 minutes ago, Gypolo said:

the clutch was replaced a couple of months back. Could this have caused any problems?

Not sure; but doubt it.  May have damaged some loom wiring but if the faults have only just started appearing, it seems unlikely.

1 minute ago, Wino said:

So is the plan to take it back to the garage tomorrow, or have you got a scan tool coming?

Maybe look to see if there's a member with VCDS near you: https://www.briskoda.net/forums/topic/262215-list-of-vcds-owners-previously-known-as-vag-com-vcp-owners/?tab=comments#comment-3091029

Not sure; but doubt it.  May have damaged some loom wiring but if the faults have only just started appearing, it seems unlikely.

Yes the plan is to take it back tomorrow to get codes re read and see what else they can do. I'll ask him to reset ECU as mentioned earlier to see if that fixes it.

 

I'll probably order the sensors myself to try this as a cheap fix but if problem remains I'll have to book it back in and let them have a look.

 

My cousin has a diagnostics device that I'll hopefully pick up at the weekend.

10 hours ago, maccy said:

Is there a non-return valve on the servo pipe ? Is there any chance it could be on backwards ? That would make the brakes very poor indeed.

 

See if you can get the exact fault codes and then we can assist in more detail.

1 hour ago, Gypolo said:

Yes the plan is to take it back tomorrow to get codes re read and see what else they can do. I'll ask him to reset ECU as mentioned earlier to see if that fixes it.

 

I'll probably order the sensors myself to try this as a cheap fix but if problem remains I'll have to book it back in and let them have a look.

 

My cousin has a diagnostics device that I'll hopefully pick up at the weekend.

 

 

The cam position sensor fault alone would force the car into limp mode, you're going to need to check the wiring to the sensor if the sensor itself is ok, it's possible the loom was strained when the clutch was changed if the garage were really sloppy.

so I just went and bought a OBD II scan tool and it is refusing to link to my car, despite the garages snap on having no problem whatsoever.

 

Thought I would check the wiring instead of just setting fire to my car and found a electrical connector just hanging there between the gear box and the starter motor.

 

Now I'm thinking that should be connected to something..... but can't for the life of me find where to relocate it.  All of the wiring at the bottom of the car is in a shocking state and looks like the garage didn't bother to re fix any of it after competing the work. Not happy.

 

 

What colour are the wires going to it?

Is that your reverse light switch just in front of the paper label? Looks like it might belong on that?

21 minutes ago, Wino said:

What colour are the wires going to it?

Is that your reverse light switch just in front of the paper label? Looks like it might belong on that?

Yes you are right, I can see why they left it off now. The shiny residue is glue that they were obviously waiting to go off before re connection after they snapped the switch