Hi All,

I'm new to the forum, I Own a Fabia 2002 1.4 MPI, I have a severe misfire problem and lack of power which has been getting steadily worse over the last few months.

The engine management light is on, usually static but sometimes flashing, being an IT guy by trade I couldn't bare taking it to a garage to watch someone plug it in to a computer, push a button and charge me £50. So I configured VAG-COM on my laptop, got a cable off ebay and these were the results,

8 Faults Found

16502 - Engine Coolant Temp. Sensor(G62): Signal too high

P0118 - 35-00--

17978 - Engine Start Blocked by immobilizer

P1570 - 35-10--- Intermittent

16684 - Random/Multiple cylinder misfire detected

P0300 - 35-10--- Intermittent

16686 - cylinder 2 misfire detected

P0302 - 35-10--- Intermittent

16687 - cylinder 3 misfire detected

P0303 - 35-10--- Intermittent

17549 - Load Calculation cross check: Implausible value

P1141 - 35-10--- intermittent

16688 - cylinder 4 misfire detected

P0304 - 35-10--- Intermittent

16685 - cylinder 1 misfire detected

P0301 - 35-10--- Intermitent

I hoping someone can point me in the right direction of where to start with diagnosing the faulty component(s).

Edited 29 December, 201114 yr by bonio456

Clear all the faults, take for a test drive and rescan. The ECU won't get rid of codes unless they are erased, it will downgrade codes to intermittent if they haven't ocurred over a few driving cycles.

It seems like the only live code is the temperature sensor one, when the engine is cold remove the sensor and check the thermostat, it may well be broken inside and touching the sensor. A replacement thermostat comes complete with sensor, part number 047121111S is around £40.

I had a misfire code when I got hold of mine for cylinder 1. Changed the spark plugs, cleared the codes, never came back. The start blocked by immobiliser seems to come up when the battery is knackered.

The load cross calculation check I've never come across. This link http://wiki.ross-tech.com/wiki/index.php/17549/P1141/004417 suggests it points to a faulty MAP sensor (is what it would be on the MPI), but I have a feeling that rather than the sensor itself it is related to the misfire. Worth checking the integrity of the vacuum servo hose (from inlet manifold), and that the manifolds are not blowing (or more precisely sucking).

To sum up +1 on above. Clear codes. New thermostat housing and temp sender (comes as one unit). New spark plugs if you have no idea when they were done and the car's done more than 40k miles. Skoda specify they should be replaced at 40k miles, so if they've never been changed and your car is now on something like 80k you've done well. Basic maintenance is always good, so if oil and filter hasn't been done in over a year/10k miles worth doing that too.

Thanks guys, I've cleared the codes and bought the service bits this morning.

I will check out the suggested causes and post my findings.

Thanks for all your help

SWMBO has a 1.4 MPi with loads of diagnostic faults as well (but different symptoms) - so I'll be keeping an eye on this post and adding anything I come up with which may be of use to you.

Today I removed the MAP sensor, gave it a clean with some maintenance spray, after putting it back in there was a major improvement on the misfiring, although still not perfect so a new sensor has been ordered, £30 on ebay. Then started replacing the plugs, the ones out of cylinders 4,3,2 seemed ok a bit scorched but apart from that ok, however the one in cylinder one was loose and completely black. This again had further improvement on the misfire, the engine management light now goes on and off when driving instead of being on constantly.

Retested with vag-com and only have these faults now

16684 - Random/Multiple cylinder misfire detected

P0300 - 35-10--- Intermittent

16686 - cylinder 2 misfire detected

P0302 - 35-10--- Intermittent

16688 - cylinder 4 misfire detected

P0304 - 35-10--- Intermittent

I will update again once new sensor arrives, does anyone know where the fuel filter is as I couldn't find it today?

A map sensor is unlikely to cause a misfire as its not cylinder specific.

I have a spare coil pack if that's any good to you. It's either going to be that or an injector.

Fuel filter is on the drivers side next to the fuel tank.