Evening All,

 

Following on from the saga that was the ignition wiring burnt out, and subsequently replacing wiring and diode, car ran well for a few days, albeit with the ESC warning light and displaying a Tyre pressure monitoring fault, (on the dot display when ignition switched on and wont clear when pressing reset),  neither of which will clear with various scanners.

 

Having been stood for a while, (due to working away), I charged the battery up and it wouldnt start; it just made a small clunk like noise.

 

Battery is holding steady @ 12 + v after charging.

 

I jumped the starter motor direct from the battery, and it fired up first time. It then subsequently ran on the turn of the key, once I reconnected the ignition wire.

 

10 minutes later - back to clunk.......

 

I've now taken out the complete dashboard again, physically checked all wires and connections, (again), and no difference......

 

Anyone of you wise Skoda Sages have any ideas on what to do next for the faults and ignition problem?

 

Thanks in advance!

 

The clunk sounds like a bad solenoid, try replacing it, they're not expensive.

Its a new starter motor, approx 3 months old. Thats not to say it cant be goosed, I suppose :/

 

9 minutes ago, Zuglie said:

Its a new starter motor, approx 3 months old. Thats not to say it cant be goosed, I suppose :/

 

 

In that case there has to be a dodgy earth under the bonnet somewhere.

It may be that a device inside the BCM connected to the starter solenoid is damaged; this damage may have started when that diode failed. I seem to remember thinking that the diode's probable function was protection for just such a device.

 

 

 

A diode is usually used to prevent voltage flowing back from a coil or a DC motor, if the BCM were damaged the issue wouldn't be intermittent.

The starter needs a very good earth from the engine block to the chassis so I'm wondering if there's a damaged earth.

Earth connection fault certainly possible and easier to mend.

Ignition switch?

If the starter works well when the solenoid is given direct power from the battery, and in the recent past there has been a short-circuit drawing excessive current through the ignition switch contacts...

Thanks Gents!

 

I left the battery on the car last night and it was down to around 7.5v, so it would seem I also have a drain somewhere.

 

I've also ordered a new ignition switch, to rule that out at least.

 

Will check the starter earthing out and once battery is charged, will try and find the route of the drainage.

 

Will keep you posted.

 

That may just be the only/real problem. Make sure you find that current drain if you can measure one, otherwise any battery you fit is going to have its effectiveness and lifetime badly compromised.

Quick and dirty parasitic current measurement - Handy Topics & Guides - BRISKODA

The car that keeps on giving!

 

Battery fully charged, connected to car, hazard lights flashing, Hazard lights switch disconnected and all 645 relays removed, BCM clicking away; is the BCM gone?

 

 

Possibly; the indicators will be powered by a chip inside it, no relays involved I believe.

Can you remove the  BCM and  inspect its innards for any signs of damage?

Clips on side may undo, but seems to be held by these pins🤷‍♂️

Sorry, no idea how it might come apart.  Might be designed not to without breakage if you're unlucky.

cant seem to find a match online, neither...:(

 

Similar numbers, but the last letter being an M or H

 

Part number: 6R7 937 087 R

Is that cover with the part number sticker integrated with the connectors, or are they separable? Might be some 'ramp catches' between connector bodies and lid, as well as down the edges, so the other cover stays attached to the board, but that cover comes away?

There are a couple of holes that might have screws down them, visible in that shot too.

Definately wont come apart without breaking it - tried everything

 

Slightly different number, but has 2 additional pins on top right to mine - would this matter?

Do these need to be coded to the car also?

NVM - different size and layout - probably wont fit! :(

 

Don't know the answer to either, sorry.

 

Are the things in your first photo, on the back of the unit, plastic pegs that might pull out, or are they melted over?

Edited 3 August, 20214 yr by Wino

Hi Guys, 

Quick update;

 

Replaced BCM with 2nd hand one, exactly same part number.

 

Replaced 3 month old battery with brand new one.

 

Replaced starter switch.

 

Car starts on the button, left overnight with battery connected no drain, car started.

 

Fault codes showing:  sterring angle sensor, TCM and media system?

 

Completed manual reset of steering, turning left/right, and reset fault codes.

 

TCM and media still showing?

 

Also since changing BCM, the remote central locking doesnt work, but all locks lock from drivers door. Does the BCM require coding?

 

Few more checks then the big dash reassembly begins!

Try whatever remote fob pairing procedure you might find in the Owner's Manual, as a start?

TCM fault may need a short drive to reset itself? (Sheer guesswork)

Media; not sure about, does the radio work?

 

If it all gets working can you smash your way into the old unit to see what looks cooked? (Not before though!)

Tried the pairing procedure - dont work.

Strange as it all works fine on the key.

 

There might be some info that needs copying across from old to new unit. Don't know what or how though, sorry.