0.3 Amp drain, 1.9 TDI ALH, Comfort control module?

[Ando]

Hey people,

I've got a 51 Skoda Octavia 1.9 TDI Ambiente, I've got a drain on the battery of 0.3 Amps which obviously flattens the battery quite quickly. All I know is; if I take the comfort control module (behind the dash) out before the ignition is turned on the drain goes down to 0.01 Amp which is acceptable, if I take the box out after the ignition has been turned on then the drain stays until you disconnect the battery and reconnect it.

I've tried the pulling fuses technique, the drain goes with one of the fuses so I traced the wire and found it leads to the plug connecting to the comfort control module and I'm effectively turning the box off by pulling the fuse (it keeps the drain if you pull the fuse whilst ignition is on - same as removing the box). None of the other fuses make any difference.

I've also tried pulling all the relays, made no difference.

I tested current across the fuse which controls the module, it wasn't much, something like 0.01 Amps (not the 0.3 Amps I was expecting)

I've pulled out all the lights inside the car (which all work) , removed the electric windows isolator (which all worked) , all the door and boot locks work fine but can't disconnect them easily. I've probed just about everything I can think of and now I'm out of ideas, PLEASE HELP!

The only thing I can think of is the comfort control module is turning something on and not turning it off properly but I don't want to replace it without knowing for sure.

Any help of any sort would be greatly appreciated, thank you in advance.

[pikpilot]

Hey people,

I've got a 51 Skoda Octavia 1.9 TDI Ambiente, I've got a drain on the battery of 0.3 Amps which obviously flattens the battery quite quickly. All I know is; if I take the comfort control module (behind the dash) out before the ignition is turned on the drain goes down to 0.01 Amp which is acceptable, if I take the box out after the ignition has been turned on then the drain stays until you disconnect the battery and reconnect it.

I've tried the pulling fuses technique, the drain goes with one of the fuses so I traced the wire and found it leads to the plug connecting to the comfort control module and I'm effectively turning the box off by pulling the fuse (it keeps the drain if you pull the fuse whilst ignition is on - same as removing the box). None of the other fuses make any difference.

I've also tried pulling all the relays, made no difference.

I tested current across the fuse which controls the module, it wasn't much, something like 0.01 Amps (not the 0.3 Amps I was expecting)

I've pulled out all the lights inside the car (which all work) , removed the electric windows isolator (which all worked) , all the door and boot locks work fine but can't disconnect them easily. I've probed just about everything I can think of and now I'm out of ideas, PLEASE HELP!

The only thing I can think of is the comfort control module is turning something on and not turning it off properly but I don't want to replace it without knowing for sure.

Any help of any sort would be greatly appreciated, thank you in advance.

I have assumed that you mean the convenience unit as comfort control is part of the air conditioning.

Please check the following:

1) Does the on door courtesy come on and off as expected when you open and close the driver's door

2) Does the interior light stay on and then dim a while after closing the door (ignition off), or operating the remote door lock

3) Does the door ajar/open lamp on the dashboard come on and off as expected when you open and close the boot (with all other doors closed).

4) as 3) with the driver's door.

The correct answer is yes for all questions.

If everything works correctly then I suspect the convenience unit, but this will be unusual. The convenience unit draws 0.3A until the alarm has been set - triggered by the doors being closed and locked. If a signal that the car is locked is not getting to the convenience unit, it will keep drawing the 0.3A and could flatten the battery.

Can you check the alarm works? I don't know for sure but I would guess that if the bonnet is not closed fully then the convenience unit will not be getting a signal from there and will not set the alarm and will keep drawing the 0.3A - just a guess from experience of other cars.

[Ando]

I have assumed that you mean the convenience unit as comfort control is part of the air conditioning.

Please check the following:

1) Does the on door courtesy come on and off as expected when you open and close the driver's door

2) Does the interior light stay on and then dim a while after closing the door (ignition off), or operating the remote door lock

3) Does the door ajar/open lamp on the dashboard come on and off as expected when you open and close the boot (with all other doors closed).

4) as 3) with the driver's door.

The correct answer is yes for all questions.

If everything works correctly then I suspect the convenience unit, but this will be unusual. The convenience unit draws 0.3A until the alarm has been set - triggered by the doors being closed and locked. If a signal that the car is locked is not getting to the convenience unit, it will keep drawing the 0.3A and could flatten the battery.

Can you check the alarm works? I don't know for sure but I would guess that if the bonnet is not closed fully then the convenience unit will not be getting a signal from there and will not set the alarm and will keep drawing the 0.3A - just a guess from experience of other cars.

Thanks for your reply, yes I did mean the convenience unit.

The answer is yes to all those questions, however I did notice that having the bonnet open made no difference to the light on the dash (stays off), it certainly looks as though it has a switch on the bonnet lock, I've tried tricking it but it made no difference.

One thing I did note was that the drain went down to 0.2 Amps with the doors locked however I'm pretty sure my model doesn't have an alarm, I can't find an alarm horn anywhere. I tried to set the alarm off (just incase it does have one but I can't find it) by locking the car and opening the boot, the light came on in the dash and the flashing red light remained on top of the driver's door card, however there was no alarm sound.

I'm very confused.

[pikpilot]

Thanks for your reply, yes I did mean the convenience unit.

The answer is yes to all those questions, however I did notice that having the bonnet open made no difference to the light on the dash (stays off), it certainly looks as though it has a switch on the bonnet lock, I've tried tricking it but it made no difference.

One thing I did note was that the drain went down to 0.2 Amps with the doors locked however I'm pretty sure my model doesn't have an alarm, I can't find an alarm horn anywhere. I tried to set the alarm off (just in case it does have one but I can't find it) by locking the car and opening the boot, the light came on in the dash and the flashing red light remained on top of the driver's door card, however there was no alarm sound.

I'm very confused.

I had always assumed that my car had an alarm, as indeed had my previous cars. I looked in the drivers manual and it said the alarm was an optional extra. It also said that safe mode can be changed by pressing the remote lock mode button twice within 2 secs (indicated by suppression the door LED) and that this feature does not operate when an alarm is fitted. So I experimented - the flashing LED on the drivers door can be inhibited by the double press on the key button, so proving that an alarm is not fitted.

The current falling to 200mA instead of nearly zero suggest another circuit is still active outside of those controlled by the convenience unit - a circuit that is normally active when the vehicle is locked. The power being taken is around 2.5W which suggest either a light bulb or the radio. I mention the radio because because you can set it up to remain on at all times and if the volume is turned down you would not notice. Just a thought. I guess you now need to trace where the current is going by using a clip on dc ammeter or by pulling fuses.

[Ando]

I had always assumed that my car had an alarm, as indeed had my previous cars. I looked in the drivers manual and it said the alarm was an optional extra. It also said that safe mode can be changed by pressing the remote lock mode button twice within 2 secs (indicated by suppression the door LED) and that this feature does not operate when an alarm is fitted. So I experimented - the flashing LED on the drivers door can be inhibited by the double press on the key button, so proving that an alarm is not fitted.

The current falling to 200mA instead of nearly zero suggest another circuit is still active outside of those controlled by the convenience unit - a circuit that is normally active when the vehicle is locked. The power being taken is around 2.5W which suggest either a light bulb or the radio. I mention the radio because because you can set it up to remain on at all times and if the volume is turned down you would not notice. Just a thought. I guess you now need to trace where the current is going by using a clip on dc ammeter or by pulling fuses.

]

I've checked all the obvious stuff such as lights and stuff and I've checked the radio. Pulled fuses and done ammeter checks, nothing draws 0.3 amps from the fuse box but removing a fuse takes the drain away by turning off that convience unit.

[Wardy]

Have you had a diagnostic (VAG-COM/VCDS) scan done? It could be that a part of the convenience coding is incorrect, and leaving a function on that shouldn't be.

[Ando]

Have you had a diagnostic (VAG-COM/VCDS) scan done? It could be that a part of the convenience coding is incorrect, and leaving a function on that shouldn't be.

I've put a Snap-On diagnostic tool on it but found nothing.

:(

[felicia16v]

I've put a Snap-On diagnostic tool on it but found nothing.

:(

no good it wont go as deep as vagcom does, i would try and find someone local who can use vagcom to check coding options and maybe change a few bits to check

[mannyo]

The snap-on one might not be good enough, you need something that can read and display the coding of the module. You can then look at the list of what it thinks that it has connected to it against what it really has. VCDS (VAG-COM) does just that in a user friendly manner.

[Ando]

The snap-on one might not be good enough, you need something that can read and display the coding of the module. You can then look at the list of what it thinks that it has connected to it against what it really has. VCDS (VAG-COM) does just that in a user friendly manner.

So am I right in saying that if I buy this VAG COM thing then I'll be able to turn off bits within that module? Or will it just tell me information about it?

[mbames]

Rather than shelling out on vag-com to start with, there are a number of members around the country who are willing to scan/do stuff in exchange for a few beer vouchers / etc.

[Wardy]

If you give a bit more profile info rather than just 'England' we might be able to point you in the right direction (!!) - that section of profile info is there for a reason you know

But yes, VCDS has the ability to fully control the coding of modules.

To give you an example, I removed the OEM Skoda Bluetooth module from my Octy Mk2 and didn't de-code it from central convenience. It drained my battery fully and completely by the next time I went to use the car

[johnrr]

I have a very similar problem on my y reg elegance estate. If I disconnect and reconnect the battery the fault clears. Once the key has been turned the drain is back on; 2 to 3 hundred milliamps - enough to flatten a good battery in a couple of days. Once the fault is present the door open warning light fails to work ( it works after the battery has been disconnected and reconnected) Another couple of problems which may or may not be connected: isthe courtesy light stays on for about 5+ minutes after the door is closed although it goes out when the car is locked or the engine is started, and the sunroof no longer closes with the windows when I hold the remote lock button down or hold the key in the locked position in the driver's door. I have had the car into two dealers, one franchised and one non-franchised, each having the manufacturers diagnostic equipment but neither has been able to fix the problem. Couls it be a fault in the convenience control unit? Any more ideas anybody?

[mbames]

The mk1 octy can only close the sunroof with the key turned in the lock, and not via a button in the keyfob, unless something like the alientech mod has been fitted into the loom in the drivers door - or certainly that is my understanding (as I have an alientech unit).

My courtesy stay on for a few seconds (probably under a minute), if I don't start / lock the car, sure it does not stay on for 5+ mins... so maybe you have a fault in your convenience unit, but I certainly would not say that with much conviction from the problems stated (ignoring the current draw)

[hebails]

Just to resurrect an old thread I have the same problem with my CCM on my X plate Octy and have been quoted £400 to source and fit the part from Skoda but have just been told there is a backorder on the part. I've just sourced the part for £30 from a breakers so am wondering if I pop the old one out and fit the new one (will take about 10 minutes I'm guessing) will I then need a special tool to code the new module with the existing keys or can it be done by a third party?

Cheers

Paul

[Ando]

I think you'll find the modules are one time only coded. I don't think a second hand unit will work.

I replaced my unit with a new one and it fixed it.

[rwbaldwin]

I think you'll find the modules are one time only coded. I don't think a second hand unit will work.

I replaced my unit with a new one and it fixed it.

The modules can be recoded but more often than not any existing settings will work fine.

[neilcaldwell]

^{My guess is your radio. Why not pull the plug on the back of the radio and test. Just a hunch but that was flattening my battery.}

[marcp]

Sorry to bump an old thread but beats starting a new one, my Octy needs a new CCM, but all I am trying to find out is, can I use a CCM from a simalar spec and age of car, but with a different part number, and is it also plug and play, no fooling around coding it, some things I read say the CCM is coded to the key, others say not! :(

[BrownBarge]

Try and find one with the same part number. And once fitted you will need vcds to code your keys to it. Assuming you have remote locking that is.

[rwbaldwin]

Sorry to bump an old thread but beats starting a new one, my Octy needs a new CCM.../quote]

What makes you think you need a new CCU?

[marcp]

Had issues with central locking, interior lights and boot locking. Replaced entire loom and control unit and latch in drivers door, now have alarm LED working, remote locks, and leccy mirrors fully functioning.

Boot lid still does not lock or unlock, and interior lights don't function at all, regardless of where the switch is, and neither do the maplights. Getting no power to boot lock solienoid when operating, fuses are all fine, I did have a code from a scan I did few days ago but in all honesty ive forgotten since then.

[whitep]

when you have a drain I always pop the cable off the alternator or the end near the battery... it might be a failing diode?

[BrownBarge]

Had issues with central locking, interior lights and boot locking. Replaced entire loom and control unit and latch in drivers door, now have alarm LED working, remote locks, and leccy mirrors fully functioning.

Boot lid still does not lock or unlock, and interior lights don't function at all, regardless of where the switch is, and neither do the maplights. Getting no power to boot lock solienoid when operating, fuses are all fine, I did have a code from a scan I did few days ago but in all honesty ive forgotten since then.

I had the same issue with the boot lock. That was the ccu too

[GNPerkins1]

Which fuse is N°14?