Struggling with intermittent P1142 (accompanying breakdown))

[dant158]

Hi All, just throwing this out there in the hope someone may have experience with similar issues.

 

I'll preface this with the disclaimer that I'm no great shakes at working on cars, beyond owning an ODBeleven code reader and a computer to google things with.

 

I've been struggling with some persistent fault codes and warning lights on the missus Fabia 1.4 Ambiente (56 reg). the car was serviced regularly by the first owner, up until about 5 years ago, when the last owner took over. The service history is pretty much blank after that, with the exception of receipts for new tyres every now and again. We've had it for approx a year now (it's not driven much, for reasons that are about to be explained, lol)

 

Typical behaviour I see is:

Clear the codes

Drive for half an hour or so

EPC/Engine warning light comes on, sometimes also the traction control (ASR) light also

If the ASR comes on, the car is perilously close to what I can only describe as dying. The power to the engine seems to cut completely, with no throttle response (this has only happened at motorway speeds so far). I get pulled over and turn it off and back on again (sometimes needs a few minutes to 'calm down' before coming on, and the EPC/Engine warning light stay on, but it's running.

Bring it home and do a code scan, usually with it returning something like this (items with 'no trouble codes'  removed):

 

 

VIN: TMBND46Y174149101
    Car: Skoda Fabia
    Year: 2007
    Body type: 5-dr hatchback
    Mileage: 168020 KM

---------------------------------------------------------------
01 Engine

    System description: MARELLI 4MV        5954
    Software number: 036906034DF
    Coding: 00071

    Trouble codes:
        P1142 - Load detection value below lower limit
            Intermittent

---------------------------------------------------------------
03 Brakes

    Software number: 6Q0907379AG
    Software version: 0002
    Hardware number: 6Q0907379AG
    Serial number: 00000000000000
    Coding: 0002178

    Trouble codes:
        01314 - Engine control module (ECM) Please read DTC
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 237
                Mileage: 167999 km
        P1857 - Load Signal Error Message from Engine Contr.
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 237
                Mileage: 167999 km
---------------------------------------------------------------
08 Air Conditioning

    System description: Klimaanlage        X0840
    Software number: 6Y0820045

    Trouble codes:
        01596 - Fresh/recirc. air flap position motor Open circuit/short circuit to B+
            static
        01596 - Fresh/recirc. air flap position motor Adaptation did not occur
            static
---------------------------------------------------------------

 

A few other codes have popped up, but the P1142 seems to be the only consistent one.

 

I've had it cut out a couple of times on the motorway (thank god it was me driving at the time, and not the missus), so obviously it's not inspiring confidence for her to drive.

 

Things I've (attempted to) check:

Battery voltage (off, start-up and while running)

Brake light illumination

Servo pipes (one found in bad shape and replaced)

Throttle body cleaned

EGR (sort of) cleaned

Front O2 sensor continuity

Spark plugs (but not coil packs, which has just popped into my head as I type this)

The little connector by the gearbox that I've read is the load cable from the alternator and is apparently a common brake point.

 

I'm pretty much as a loss  for where to go next.

We've been to a garage for a diagnostic, but the lights were off at that time, so no help there. In my head, because common codes seem to indicate comms problems, that there must be a broken wire somewhere in one of the looms, but wouldn't feel confident enough to even begin to guess where.

 

Has anybody got any experience with similar? Any suggestions? I'd even be up for getting a VCDS cable, if it can potentially shed more light than my OBDeleven device. But really at this point, I'm open to any advice on where to look or what to do. If somone has this exact problem and a resolution, that would be amazing too :P

 

[Breezy_Pete]

Have you changed the engine air filter since acquiring the car?

Is there any history of cambelt change ever?

It would at least be worth getting VCDS lite (free download from Ross-tech) and a suitable cable interface (<£20). That would probably give you more and better fault info, and potentially, with a 99USD upgrade to 'registered' status, the ability to do things like throttle body adaptation, amongst many other things.

 

Edited 25 September, 2020 by Wino

[Andymod]

Load detection fault is normally caused by a broken wire in a 2 pin connector block down in front of the gearbox. It's best accessed from underneath.

 

[dant158]

On 25/09/2020 at 06:43, Wino said:

Have you changed the engine air filter since acquiring the car?

Is there any history of cambelt change ever?

It would at least be worth getting VCDS lite (free download from Ross-tech) and a suitable cable interface (<£20). That would probably give you more and better fault info, and potentially, with a 99USD upgrade to 'registered' status, the ability to do things like throttle body adaptation, amongst many other things.

 

I had not, but now you mention it I did remark that it looked dirty before. Just hadn't got around to replacing it.

I've got one yesterday morning and replaced it and the missus has a reasonably long journey this afternoon, so I'll let you know if the light comes back on.

The service history indicates the 'toothed belt' which I assume to be the cam belt was changed in 2013 / 20k miles (7 years and 80k miles ago). Is the fact that this was replaced at only 20k a big of a warning light that I missed, even though the car would have been about 6 years old by then? I wouldn't expect it would need changed in a car with so few miles.

 

16 hours ago, Andymod said:

Load detection fault is normally caused by a broken wire in a 2 pin connector block down in front of the gearbox. It's best accessed from underneath.

 

I have had a look around that connector and can't see any broken wires. But I suppose there could be some water ingress or a broken wire somewhere else in the loom.

Is there any simple continuity tests I can do that you guys are aware of to test the loom without having to manually inspect the entire length?

 

Thanks for the help so far all!

[Breezy_Pete]

Cam belts are often on a time or mileage schedule (whichever comes first), so probably done on age previously. 

Not sure that 'load' in this fault code is the same as that relating to alternator DFM wire. Think it's engine load instead.

 

[sepulchrave]

http://wiki.ross-tech.com/wiki/index.php/17550/P1142/004418

 

Nothing to do with the alternator at all.

[sepulchrave]

It sounds like the ASR system is cutting in and killing the power, try driving it with the ASR system switched off.

 

This suggests you have a problem with one of the front wheel speed sensors, have either of the front wheel bearings been replaced to your knowledge?

[dant158]

I will definitely try with the ASR off. Looks like you could be onto something there.

 

There's nothing at all in the service history, and I've looked back through all the old receipts that I got with the car and there's nothing in there about wheel bearings (though of course, that's not to say they have never been worked on). Could it be incorrect/bad bearings? Or simply old ones on the way out?

 

Missus took the car out for half a day today and did a good 60-70 miles. I fully expected lights to have come on, but nothing. We then went out for a drive this evening and all seemed fine until 5 mins from home. I was in 3rd, low rpm, but not so low as to need to shift down (slowing down for a bumpy patch on the lanes). Squeezed the accelerator, and presto - EPC, engine warning and a few seconds of ASR. Engine sounded fine, and no loss of power. Code scan as soon as we were home returned the following:

 

Date: 2020-09-27 20:00

    VIN: TMBND46Y174149101
    Car: Skoda Fabia
    Year: 2007
    Body type: 5-dr hatchback
    Mileage: 168290 KM

---------------------------------------------------------------
01 Engine

    System description: MARELLI 4MV        5954
    Software number: 036906034DF
    Coding: 00071

    Trouble codes:
        P1142 - Load detection value below lower limit
            Intermittent
        P1553 - Altitude sensor signal/intake manifold pressure Implausible ratio
            Intermittent
---------------------------------------------------------------
03 Brakes

    Software number: 6Q0907379AG
    Software version: 0002
    Hardware number: 6Q0907379AG
    Serial number: 00000000000000
    Coding: 0002178

    Trouble codes:
        01314 - Engine control module (ECM) Please read DTC
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 38
                Mileage: 168289 km
        P1857 - Load Signal Error Message from Engine Contr.
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 38
                Mileage: 168289 km
---------------------------------------------------------------
08 Air Conditioning

    System description: Klimaanlage        X0840
    Software number: 6Y0820045

    Trouble codes:
        01596 - Fresh/recirc. air flap position motor Open circuit/short circuit to B+
            static
        01596 - Fresh/recirc. air flap position motor Adaptation did not occur
            static

 

Cleared them and seems ok. Will make a point of driving without the ASR the next few days and update.

 

Thanks for the help so far, all. Really a good learning experience for me!
 

 

 

[dant158]

So, we have been driving this past week or so with the ASR system switched off.

All seemed to be well until Friday evening on the way back home, we had the dreaded EPC/Engine warning combo (ASR already illuminated as the system was disabled) but made it home, no dramas.

 

Code scanned as soon as home and got this ('no trouble codes' ommitted):

 

Date: 2020-10-02 21:11

    VIN: TMBND46Y174149101
    Car: Skoda Fabia
    Year: 2007
    Body type: 5-dr hatchback
    Mileage: 168340 KM

---------------------------------------------------------------
01 Engine

    System description: MARELLI 4MV        5954
    Software number: 036906034DF
    Coding: 00071

    Trouble codes:
        P1142 - Load detection value below lower limit
            Intermittent
---------------------------------------------------------------
08 Air Conditioning

    System description: Klimaanlage        X0840
    Software number: 6Y0820045

    Trouble codes:
        01596 - Fresh/recirc. air flap position motor Open circuit/short circuit to B+
            static
        01596 - Fresh/recirc. air flap position motor Adaptation did not occur
            static
---------------------------------------------------------------
56 Radio

    System description: Radio YD5          0015
    Software number: 6Y0035156E
    Coding: 00401

    Trouble codes:
        00879 - Connections to right speakers Open circuit
            Intermittent
 

 

If I get some dry weather and daylight I'll have the front wheels off in the week and inspect the speed sensors and/or bearings for any obvious looking problems like play in the bearings or maybe a broken sensor or something.

 

Will keep this updated of findings.

 

[sepulchrave]

You have an air leak, probably the vacuum pipe to the brake servo, check all the pipe joints for splits wherever they're shrunk onto a hose barb.

You definitely have a front wheel speed sensor issue, often the reluctor ring is damaged during incorrect front wheel bearing fitment rather than the sensor itself.

[dant158]

Better late than never for an update!

 

Having left the car into a dealer to have a look at and with a few unsuccessful attempts by them to rectify the issue, we were at our wits end. As a bit of a last ditch effort before getting rid of the car I decided to take a stab at just chucking a new throttle body in the car. The logic behind it being that with a pressure warning being the symptom and the garage having tried everything else that could possibly be related to manifold pressure the only remaining thing I could think of was that there must be some sort of disconnect between where the ECU thinks the butterfly valve in the throttle body is, with where it actually was positioned.

 

I got a cheap aftermarket throttle body, plugged it in and performed the adaption, 1000+ miles later and still have not had the recurrence of the issue, so looks like problem may well be solved!

 

I tried to perform an autopsy on the old throttle body, and after prying apart the swaged cover (why, oh why they don't just have some bolted configuration for serviceability I will never be able to fathom!) could not see anything obviously wrong with the gears and other paraphernalia in there, so my working assumption is that there was an electrical fault with one of those electromagnetic devices in there.

 

 

Onto the next problem - figure out why she's consuming a little engine coolant! No rest for the wicked!

[sepulchrave]

2 minutes ago, dant158 said:

Onto the next problem - figure out why she's consuming a little engine coolant! No rest for the wicked!

 

That'll be a small radiator leak, look for signs down in the bottom right hand corner.

[raky]

On 03/06/2022 at 11:57, dant158 said:

Better late than never for an update!

 

Having left the car into a dealer to have a look at and with a few unsuccessful attempts by them to rectify the issue, we were at our wits end. As a bit of a last ditch effort before getting rid of the car I decided to take a stab at just chucking a new throttle body in the car. The logic behind it being that with a pressure warning being the symptom and the garage having tried everything else that could possibly be related to manifold pressure the only remaining thing I could think of was that there must be some sort of disconnect between where the ECU thinks the butterfly valve in the throttle body is, with where it actually was positioned.

 

I got a cheap aftermarket throttle body, plugged it in and performed the adaption, 1000+ miles later and still have not had the recurrence of the issue, so looks like problem may well be solved!

 

I tried to perform an autopsy on the old throttle body, and after prying apart the swaged cover (why, oh why they don't just have some bolted configuration for serviceability I will never be able to fathom!) could not see anything obviously wrong with the gears and other paraphernalia in there, so my working assumption is that there was an electrical fault with one of those electromagnetic devices in there.

 

 

Onto the next problem - figure out why she's consuming a little engine coolant! No rest for the wicked!

Hi , Thanks for sharing info please, Sorry for bothering you , May I know please ,do u think P1142 is throttle body please ??  I don't have power loss but definitely get at least once   EPC + Engine light (Have small leak on Steering rack as well )  in 30 miles driving only  on high speed of 70miles roads possibly during change of lane. Suspect throttle body or wheel sensor may be causing issue.  I am seeing 3 more codes P1176  P1196. and P1178 but very confident O2 bank1 MAY not be Faulty ... Suspecting vacuums leak or o2 sensor bank2 may be issue , few months back made mechanic to cut open and look for catalytic converter and it was very healthy and even made him clear with air pressure as well.  At the moment engine light has came up permanent , I had coolant leak which is not any more after adding leak stop chemical in coolant. 

My throttle body is cleaned even cleaned few months by spraying EGR cleaner  without opening. 

 

17550, P1142.    Mass Air Flow Sensors (G70) faulty , Intake Air System faulty/leaking (false Air) , Throttle Pedal faulty ,Throttle Body dirty/faulty

 

 

Cheers 

raky

Edited 19 February by raky