Dear all,

 

I own a Skoda Fabia 1.4, Hatchback, petrol, motor BBY 1.4l 4LV 55 kW, year 2004.

 

In 2019 the EML light turned on. The official Skoda garage said it was an sporadic problem with the oxygen sensor. No distinguishable consequences for more than a year. Afterwards, the EPC light started to turn on too, with the engine stalling  (most of the times) right after the EPC light turned on. Turning off the car, waiting 10-20 seconds and starting the car again solved it for some days.

 

I checked the fault codes and I had these: P0135 (oxygen sensor), P0106 (MAP sensor) and P1183 (???).

 

So, I replaced the front oxygen (lambda) sensor and cleared the errors. A couple of weeks later the EML light turned on again, but this time only one error remained: P0106 (MAP sensor).

 

I also replaced the MAP sensor and everything went OK for a month or so. Then, the EML light reappeared: P0106 MAP sensor error code again!

 

The EPC light and engine stalls returned some weeks later (only P0106 fault code). But last week, the motor started jerking and I found I had P0106 and some new errors: P0135 (Oxygen sensor error was back!!!) and P1178 (???). P0106 fault code appeared recorded twice.

 

Searching here on Briskoda, I saw similar problems were caused by an old battery. Mine is 3 years old and was giving 12.02 V with the engine stopped, so I decided to change it.

 

With the new battery the problems (EML and EPC, fault codes P0106 and P0135) are also there. I would say they appear earlier now: some seconds after starting the car rather than some minutes with the old battery.

 

I feel hopeless now, because I see no other way to solve the problem. It's getting worse and I've run out of ideas. :((

 

Do you have any clue what can be causing this, given I have already changed the oxygen sensor, the MAP sensor and the battery?

 

The alternator seems to be working OK: I get between 14.2 V and 14.4 V measured on the battery with the engine started.

 

When I replaced the MAP sensor, it was surprising to see that although the sensor was supposed to be screwed to the motor with two screws, it had none: instead, a plastic-like clamp hold the sensor in place. I supposed both methods would be equivalent and then I checked the MAP sensor from a friend of mine's Skoda, and it was also screw-less. Do you think the situation would improve by putting two screws to the MAP sensor?

 

Many thanks in advance...

Maybe completely wrong but worth checking anyway, what's the pipework like (e.g. the hose between the brake servo and the engine)? Is there any breaks in the pipework, particularly at the ends where it connects.

Don't just go on raw error codes on something like this and also consider that other issues may be there causing or related to this problem (and unrelated).

Start with the basics before moving on.  You have dealt with the battery, you have checked the alternator.

 

How long did you have the battery disconnected at change over, if not overnight then try that and turn your lights on and other electrics after disconnecting the battery to loose any stored electric (don't forget to turn them back off).  Take the opportunity to give the battery a long low slow recharge.  When you reconnect the battery check for stored error codes and wipe them before you start the car.  Costs nothing but a little time and effort to try this so if it don't work you've lost very little and if it does well happy days. 

 

Have you checked all the new parts fitted are sealed as fitted.

 

What is the service history, has the airfilter been checked/changed, air box and ducting cleaned inside.

 

All hoses. pipes and ducting connected and sealed, no splits in any or connectors.  No leaks or blows on intake and exhaust  hoses, pipes gaskets.

 

Any damage or restriction to the exhaust

 

Are all the electric cables and connectors to the sensors and back to computers are in good condition, sealed connections without fur on the pins inside, cables all insulated and secured to car.

 

The MAF on my wife's car has reinforced holes for screw but is just a push (IIRC) click fit.

 

Edited 4 December, 20214 yr by nta16
spelling

@AnnoyingPentium has given you an excellent suggestion. The MAP sensor is fine just clipped in, screws will not change anything.

When were the spark plugs last inspected or changed?

6 hours ago, nta16 said:

Don't just go on raw error codes

 

Expanding on this...

 

Error codes can be helpful with certain issues. However, they're not always the most accurate all the time. Sometimes these things require the use of your head and its problem-solving skills.

Thank you, guys! You are great! I was clueless and you have opened some new paths to an eventual solution.

 

In the past few days I've been collecting the information you asked for and making tests trying to identify patterns, because after I changed the battery there ARE some changes in the way the car reacts that seem positive to me.

 

Let me first answer your questions:

On 22/11/2021 at 07:18, Wino said:

@AnnoyingPentium has given you an excellent suggestion. The MAP sensor is fine just clipped in, screws will not change anything.

When were the spark plugs last inspected or changed?

 

@Wino, I'm happy to know the MAP sensor is OK just clipped in: you have saved me time by discarding that hypothesis. Thanks!

 

Regarding the spark plugs, they were changed on february 2020.

 

On 22/11/2021 at 02:10, nta16 said:

Don't just go on raw error codes on something like this and also consider that other issues may be there causing or related to this problem (and unrelated).

Start with the basics before moving on.  You have dealt with the battery, you have checked the alternator.

 

How long did you have the battery disconnected at change over, if not overnight then try that and turn your lights on and other electrics after disconnecting the battery to loose any stored electric (don't forget to turn them back off).  Take the opportunity to give the battery a long low slow recharge.  When you reconnect the battery check for stored error codes and wipe them before you start the car.  Costs nothing but a little time and effort to try this so if it don't work you've lost very little and if it does well happy days. 

 

Have you checked all the new parts fitted are sealed as fitted.

 

What is the service history, has the airfilter been checked/changed, air box and ducting cleaned inside.

 

All hoses. pipes and ducting connected and sealed, no splits in any or connectors.  No leaks or blows on intake and exhaust  hoses, pipes gaskets.

 

Any damage or restriction to the exhaust

 

Are all the electric cables and connectors to the sensors and back to computers are in good condition, sealed connections without fur on the pins inside, cables all insulated and secured to car.

 

The MAF on my wife's car has reinforced holes for screw by is just a push (IIRC) click fit.

 

 

At changeover I left the battery disconnected for a minute or so. I agree with you that it costs nothing to let all the circuits discharge, so I removed the battery for about 24 hours, turned the lights on after disconnecting it, turned them back off, reconnected the battery and wiped the error codes before I started the car. The EML and EPC lights were off, but unfortunately they reappeared 4 minutes later.

 

The airfilter was changed on April 2021.

 

The electric cables seem OK. No fur or rust on the pins inside. Both MAP and oxygen sensor cables are secured to the car.

 

However, I've noticed the D-connector the oxygen sensor connects to has the tab broken. I mean, the tab you put your finger on to press and release the connector. However, the connector seems to be firmly locked to the oxygen sensor connector. Do you think the broken tab may be causing bad electrical connections anyway?

 

On 22/11/2021 at 00:21, AnnoyingPentium said:

Maybe completely wrong but worth checking anyway, what's the pipework like (e.g. the hose between the brake servo and the engine)? Is there any breaks in the pipework, particularly at the ends where it connects.

 

Your question is the most difficult to answer, @AnnoyingPentium: I see no way to check whether there is any breaks in the pipework because I have no access to a car lift. I suppose the only way to properly check for breaks is to visually inspect the pipework from underneath it, isn't it? Any other approach like kneeling and trying to spot some smoke popping out of the pipework? Thanks!

And now, let me tell you about the changes after I changed the battery.

 

I wrote my first post (in despair) the day after I changed the battery. Nothing seemed to have changed then, but in these days I have noticed a clear improvement (although both the EML an EPC lights keep turning on -and off!- from time to time).

 

First big difference: the car has not stalled any single time in these 12 days. Not even when the EPC light turns on. This was simply imposible before I changed the battery: the car stalled seconds after the EPC light turned with a 90% probability. Now I feel no noticeable behavior when the EPC light turns on. Furthermore, the EPC light turns on less often now. It's been off for more than a week. That was unbelievable before: it usually turned on every day or every other day.

 

Why should a new battery cause this improvement? Does that give you any clue as what could be still causing the problem?

 

Thank you SO much again.

1 hour ago, briskodafan said:

Why should a new battery cause this improvement?

Yes a lot of people find this hard to believe or follow but just have a look at some threads on here for conformation.  The car battery and its condition and connections have been very important since its use but even more so with the more modern cars as they are loaded down with computers, these computer don't like a low level of battery charge and because the various computers are so invasive and their programs so complicated (or over complicated in the case of VW, wonder why) they can throw all sorts of unexpected wobblies.  Even if the car starts and the lights seem bright enough the battery could still be too low, the programs are fighting to keep things going. By the time the 'Warning' lights, er, light it could all be too late.

 

The D-connector the oxygen sensor if it's firmly connected then the tab is of little loss - if it's easy to get at you could try parting it and checking it for crud and bent pins and then give it a spray with electrical contact cleaner both sides - but perhaps that can wait if things continue to improve as sometimes it's better leaving well alone.

 

For AnnoyingPentium's checks I think he means under the bonnet.

 

I think I might try deleting the codes with the scanner and seeing if that helps speed up recovery or record live data or freeze frame and come back here with any error codes and the other info.

 

Obviously don't let your battery go too low, even if it's new it can still be run down.

 

Edited 4 December, 20214 yr by nta16

1 hour ago, briskodafan said:

 

Your question is the most difficult to answer, @AnnoyingPentium: I see no way to check whether there is any breaks in the pipework because I have no access to a car lift. I suppose the only way to properly check for breaks is to visually inspect the pipework from underneath it, isn't it? Any other approach like kneeling and trying to spot some smoke popping out of the pipework? Thanks!

 

The pipe goes from the air filter at the top, so can be done from under the bonnet. I'd send a photograph but it's getting rather dark. I'm sure another member could do so however.

Edited 4 December, 20214 yr by AnnoyingPentium

3 hours ago, briskodafan said:

 

Any other approach like kneeling and trying to spot some smoke popping out of the pipework? Thanks!

 

The servo pipe is vacuum so there would be no smoke. It's a common failure item though.