Hi.

 

New member from Denmark here. I hope this is the right spot to post my problem.

 

Background: bought a used hatchback a few month back. Great shape (apparently) and no fancy upgrades. I work with electronics and mechanics, but I got zero car-experience (please don´t laugh at my stupid questions)

 

Fault-history: The car sometimes flashed the ABS-light and hand-brake light when I turned the key. The lights would stay on for a few minutes and sometimes this was followed by a "beeep". This would happen sometimes and sometimes no fault could be seen. The car drove perfectly.

 

"Funny part": the error (assuming its one and the same) developed to this: when ever i turned on windscreen-wipers or the "turn-signals" (right or left turn), the radio-sound and display would have a short brownout (no sound, blank display for 5-10 seconds). All of this happening while the car started, operated and drove fine.

 

"not so funny" part: Now the error has developed further and the engine will sometimes stop or perhaps not start when the key is turned. Once it does turn on, it drive fine (except the above "funny" part)

 

 I asked my normally trusted auto-mechanic, but he had no idea as where to start and I fear It could be pretty costly having him finding the fault. The actual repair is mot likely cheap (i guess)

 

Faultfinding so far:

• With my background in electronics I assumed a bad connection in some part of the powersupply for the dashboard/control-functions.
• As the motor actually could start and the battery has never needed an external charging the high currents to and from the battery must work. Agree?
• At first it apparently cured the problem when I "wiggled" the fuses on top of the battery. No bad fuses or corroded parts as I can see.
• I tried lifting and cleaning the big connectors to the battery. These appeared a bit loose for my liking, but otherwise looking fine.
• I'm now thinking that there is bad Ground-connection or power-connection somewhere in the chain from battery to dashboard (because it also affects radio, wipers and turn-lights).

Questions:

1. Anyone of you guys ever hear of something like this?
2. Where is the ground-point on the chassis for the dashboard?
3. Can I measure anything with a voltmeter, oscilloscope ect to aid in the faultfinding?

Kind regards and thanks for looking

 

Troels Mejer

Edited 14 January, 201412 yr by TroelsM

Update:

 

Drove home from work with no problems what so ever.

 

Measured battery voltage with engine running to 13.8V. Measured 13,7 in the cabin at the plug for the cigarette lighter.

 

The voltage measured in the cabin dips to around 12.5V when the "long lights" or back window heat is turned on, - but only for 1-2 seconds, then the voltage goes back to 13.6-13.7.

- is that normal?

 

Bonus info: The problem has worsened a lot the last two days and the last two days we have had more fog and snow than in the lost many months.

 

Kind regards Troels Mejer

Have you checked all the fuses?

Hi.

 

Ive visually checked and unplugged-plugged most of them. Any specific fuse you thinking about?

 

Based on my limited experience it is most likely not a single fuse because the problem relates so many different parts (but I might be wrong).

 

As everything works fine most of the time its definitely not a (completely?) blown fuse to a single component.

 

To my knowledge fuses dont normally die a little, - that would defeat the purpose of a fuse.

 

Please correct me if Im wrong.

 

Kind regards Troels Mejer

If you raise the rpm to about 2500, does the voltage go up to about 14.5V or does it stay at 13.8V?

Assuming the battery/alternator is OK, the problem is most likely caused by a faulty relay.

Hi

 

Thanks for the replys.

 

Will try to measure tomorrow. Do you know where the relay is placed?

 

Kind regards Troels

Two further observations:

 

1) a couple of times after ABS-light and brake comes on (together with the beeeeep), the dash-board-clock and km-counter will reset to 0.0. 

 

2) More than once when accelerating slightly in 1-2 gear or after stopping for red light the main light will dimm for 2-3 seconds along with the ABS-light comming on.

 

Strange...

 

Kind regards troels Mejer

@rwbaldwin: Just measured the voltage in the cabin to 14.0 with the revs at 2500. - but at that point the was no "funny" faults, so everything worked fine

 

Kind regards Troels

I mentioned the fuse box cause a friend had similar come and go issues. They discovered that one fuse was to blame and even though it looked ok it didn't work properly.

one more update: Just measured the voltage in the cabin to 12V with no ignition and after the car standing still for 6 hours. When i put the key in and turned the voltage droppped to approx 9V while the engine started (2-3seconds) and then jumped to 14.1V regardsless off engine revs.

 

I don´t understand this.

 

Troels

As 32K states above. It is very difficult to diagnose a blown or erratic fuse by naked eye. It would be nice if you could plug the car in a VCDS or VAG-COM to see if there are any faults kept in the ECU.

 

If there are any faults since there are warning lights it would be easier to find the source of your problems else, If there are no faults kept in ECU we can just make assumptions since it can be anything from a blown fuse, to a faulty ABS sensor or even a faulty dashboard.

Edited 15 January, 201412 yr by stratosg

Hi Startosg

 

I really appreciate you guys taking time to write here.

 

Yes, agree that a blown fuse can be hard to track and yes a ECU readout might reveal something.

 

BUT, I don´t see how a single blown/defect fuse or defect sensor could produce the faults I'm seeing.

 

Am I wrong on that assumption?

 

Kind regards Troels

I've read that there is a "voltage distributor" somewhere in the car and perhaps behind the dash somewhere?

- can Anyone verify this or is the distribution done from the connections directly on top of the battery?

 

The engine room overview:

 

And the top of the battery with some distribution:

Hooooold on.... you got an MKI?

Sorry to confuse. I got the one in the picture :-) is that enough ID on the car or shall I dig up some papers on it?

 

Should have posted earlier to clarify i guess.

 

Being a total amateur in this field I didnt think about all the versions of Skoda's out there.

 

Again: Sorry and thanks for the help and patience

 

Kind regards

Just saying that if you started this on the Fabia MKI section you might get more help and feedback.

http://www.briskoda.net/forums/forum/26-skoda-fabia-i/

Ooops. Had not realized that. I'll try to post the original question in the other section. Hope that doesn't violate rules.

 

Kind regards

If you look under the boot carpet or in the service log book, you will find a label that gives a 3-character engine code. It will help if you post that code.

I've moved the other topic and merged it with this one, so hopefully all the helpful replies will be in this topic.

I am guessing the battery is getting weak, though if its still the original one. I had dash go blank after cleaning it. disconnected and reconnected battery and back on again. Past this, it could be a myriad of faults!

Fabias are quite hard on batteries, the steering will take upto 60 amps alone.  I think that as a starting point, if it's the original battery, you're not going to do any harm in replacing it.

 

The vehicles voltage control unit is behind the dash that contains the light switch and the cubby hole, which will be to the left of the steering wheel on your car.

Voltage drop to 9V while starting means the battery is toast, I suspect your alternator brush pack also needs replacing since the charging voltage is also too low.

Hi.

 

Thanks for the help with moving the topic and the new answers.

 

I could probably try changing the battery. - The problems got a lot worse as the weather changed to colder and more foggy. Could there be some sort of "mechanical" fault with battery? - at first it usually helped to wiggle the fuses on top of the battery. - maybe it did´nt affect the fuses but some "loose" connection in the battery?

 

I'll try to measure the battery-voltage more precisely. The reading at 9V was with a DMM without min/max reading.

 

Kind regards

Anything under 12V will upset the ECU and it will start shutting down systems to try and save the power for itself.

 

The battery should read 12.8V, engine stopped with no electrical loads, 14.4V with the engine running. Anything else means problems.

Hi

 

Well, the last 3 days it´s been around zero deg cel here in Denmark and I expected the problems to worsen.

And the car has behaved perfectly for 3 days now :-/

 

To my understanding all battery-chemistry gets worse when temperature drops, but I have no experience with Lead-acid bats.

 

I've brought a voltmeter out to car and the battery-voltage is approx 12.4V with engine stopped and 14.2 with engine running.

Still dipping a lot (8-10V) when starting.

The voltmeter is checked against a trusted reference.

 

Does that mean the battery is ready for replacing? - and is that something I could do my self?

 

Kind regards Troels