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[McCabe]

Hi all, i recently picked up a 2012 Leon se Copa Edition for 2k. why 2k, well here is the kicker. The car according to the previous own just cut out and has been doing so for quiet some time. there sick of it so there loss is my gain. admittedly i am a 3rd year Apprentice Mechanic so i have quiet a lot of experience and know my way round the general car components and know how to fault process.

The car is 1.6tdi engine code Cayc. upon getting the car back home the very first thing i done was charged a battery up fully and stuck it in. put the keys in the ignition and twisted.....NO DASH LIGHTS. ok thats the first problem. spent a few mins in the car checking what was working and what was not, and kept trying the key and only once i got dash lights and pressed the clutch and she fired up, hmmmmmmm (note: this was immediately after taking the battery off charge on full and when i tried to charge up the old battery from it when my charger is showing fully charged it was putting out 9.36v so cell down in it)

The car has never once shown me the dash lights since, and hasn't fired up. off the top of my head i have indicators working and lighting on dash dipped and full headlights and showing full headlight symbol on dash. horn works wipers work radio and sat nav all working all windows working interior lighting all working central locking working boot opens no problem and because the dash had lit up the one time it did and she ran away im not convinced its an instrument panel problem.( note: the climate control on dash lights upand when i press fan speed up or down its shows on the screen etc etc but the heater blower doesnt come on so essentially i have no heater blower working) I did plug my diagnostics into the car and got back about 100 faults which i don't have anymore because my computer was updated and f****d off the saved faults file i had but not to worry. they didnt really point me in any such direction.

so i proceed Auto 3.45 up to 2014 pick out my car from the list only to find that they dont have any wiring diagrams for the car whatsoever so now my job becomes even harder. so i start brainstorming and decide well the problem at first glance is appearing to be an electrical problem. I break out my multi-meter and start doing some straight forward checks battery 12.2 volts (not to sure about this note to self im gonna lob in a brand new battery today just in-case its the obvious). Anyway voltage at main fuse-board under the hood on all wires, inside fuse box under hood checked fuses some of them are carrying 12 volts and theres is about 5 or 6 not carrying any voltage( maybe these carry a load when car is running and something is turned on by driver) power at the starter main lead, power across the solenoid cleaned battery terminals and earths around battery and fuse board. actually removed my starter and bench tested it starter is fine gave it main power from battery and earthed off the battery shorted the solenoid PERFECT also checked terminal 15 brought a live wire to that and also PERFECT. checked resistance on leads for starter and battery and carried out voltage drop tests,not losing anything. (note: I haven't gotten any voltage from terminal 15 plug that goes to starter even when i twist the key). so after i put in a new battery today I'm thinking along the lines of BATTERY, IGNITION SWITCH, FUSES, RELAYS, BAD EARTH,CONTROL MODULE AND UNFORTUNATELY ECU......

soooooooooo admittedly i haven't removed my alternator but did check if the main voltage supply to it was correct and all is fine. (dont think the alternator affects startup anyone wants to correct me please do so) im still going to do my check on alternator to see what voltage its putting out when i get the car running because it could well be the reason the old battery from the car dropped a cell. As i said previously i have no wiring diagrams, don't no what relays control what so kinda stuck here at the minute. i apologize in advance for such a long read but just trying to make things as clear as possible so you good folk out there can have an idea of what I'm dealing with. if any one has any suggestions or any possible relay numbers and what they are controlling, fuses and what they are controlling, wiring diagrams it would be MASSIVELY APPRECIATED.....

THANKS IN ADVANCE TO THOSE OF YOU WHO TAKE TIME TO REPLY TO ME.

McCabe.

 

[DrewCole]

Sounds like it could be a bargain if you can get it going...

So the engine does run, which means some things can be discounted I think, such as ECU etc... however, locate it and check for ANY signs of water ingress that could be causing problems with it.

Next I would remove clean and refit EVER earthing location on loom to be certain they are making good contact, and also the leads running to things such as Starter Motor and Alternator.

Check the main connection of the loom to the fuse panels and relay boxes to make sure there isn't any loose contacts, perhaps clean and refit anyway.

I would also take a look at the ignition barrel itself, could be that it is faulty somehow, dodgy replacement key may have damaged internal parts?

 

[Speed-FReek]

You would probably do yourself a favour by investing in a days access to erWin and then spending the day downloading all the repair manuals, wiring diagrams and other information relating to your car for permanent future offline viewing.

You can register and then log onto erWin using this link. You then need to pay for a flat hourly or daily rate to get access to any information you need. The flat rate fees are shown in this link.

 

[McCabe]

Well all i can say is thank you very much drewcole and speed freak..... i will take on board what you were saying drew iv kinda been thinking the same anyways mate ill just have to sound it out and speed freak that will be the way to go was busting my brain trying to find wiring diagrams and relays no's to find out whats what etc etc so for the replys im very greatful thanks a million.

 

[McCabe]

Well boys, just an update!! I went out for 15 mins there at the car, said id bench test all the relays under the dash. Tested them all and found a 4 pin relay labelled 373 under there that is fried. Not in stock in any of the local motor factors so ill have one Monday. here's hoping it'll be what Im looking for problem wise.

 

[Speed-FReek]

Upper or lower carrier? And which position is it in the carrier? I can probably tell you what it's for.

Is it one of the ones in the 3rd photo of this post?

 

[McCabe]

Speed -Freak its one of the ones on the lower rack not entirely sure which of the two on the bottom it is as there all hanging down out of their holders..... what are the two 373 relays for on the lower rack in that 3rd photo?

 

[Speed-FReek]

The 373 relay in position #2 of that carrier (2nd from the left) provides switched output power to the 12v cigarette lighter socket, the heater control unit, and the rear screen wiper. This is item J59 in the wiring schematic below.

The 373 relay in position #5 of that carrier (far right) provides ignition switched (terminal 15) output power to pretty much all of the components in the car which need to be powered up when the ignition is switched on. This is item J681 in the wiring schematic below.

J681 is likely the one that you've found to be fried based on your description of the symptoms the car is exhibiting.

Both of these relays are switched on and off by the Body Control Module (BCM) which is item J519 in the wiring schematic below.

 

[McCabe]

Speed freak People like you are rare man your a godsend I swapped the relays under the dash and I have all my lights on the dash and she wants to fire but she's showing esp traction faults so she won't! I'm just reinstalling the diagnostic software on my laptop I'll clear all faults and see what happens then and I'll go from there.... appreciate all your help so far you've no idea Top Bloke absolute gent

 

[Speed-FReek]

No probs

After a battery disconnection you will always get the ESC and Electromechanical Steering lights remaining on which will (should) clear if you take the car for a short drive.

However, if your engine isn't even firing up then you've obviously got some other issues to deal with first. Hopefully a diagnostics scan will help give you some clues as to what those might be.

 

[DrewCole]

Good work gents!

Sent from my SM-G935F using Tapatalk

 

[McCabe]

I actually done a before and after scan wise to the car because i know from experience about the battery been taking in and out and constant cranking can show faults. Most of the faults that were being shown were voltage lower limit threshold etc and missing messages and no communication. here i linked another battery to the one i put in the car because of the dtc's i was getting but it actually only brought my battery up to 12.28v so i wreckon most of these faults are because of poor batterys and the rear windscreen ones etc are because i sacrificed that relay for my ignition one until this morning, so to be fair im thinking that a brand new battery is the way to go because the intervention load manager i believe closes modules and circuits that it doesnt need or that it can if the ignition is left on for too long henceforth trying its best to decrease the load on and save your battery. Linked the two batterys and heres what was showing

Diesel (CAYC - TDI-CR - MT/AT)
DTC
Description
No fault codes

Brake (ABS/ESP - MK60 EC1)
DTC
Description
No fault codes

Instrument (Instrument - Diagnose)
DTC
Description
No fault codes

Climate (Climate control - Climatronic)
DTC
Description
No fault codes

Immobiliser (Immobiliser (Immobilizer) - Diagnose)
DTC
Description
No fault codes

Restraints (Airbag - Diagnose)
DTC
Description
No fault codes

Multifunction (Battery regulation - Diagnose)
DTC
Description
No fault codes

Multifunction (Central electronics - Central electronics)
DTC
Description
00446
- Function limitation due to under-voltage
- Below lower regulation limit threshold
- Intermittent

00834
- Signal for activation rear heated window
- Short circuit to ground or open circuit
- Permanent

00907
- Intervention load management
- No symptom
- Permanent

Multifunction (Door electronics - Driver door)
DTC
Description
B11EC54
- Front power window motor, no basic setting
- Permanent

B11ED04
- Rear door control unit, defect
- Permanent

Multifunction (Door electronics - Passenger door)
DTC
Description
No fault codes

Multifunction (Gateway - Diagnose)
DTC
Description
No fault codes

Multifunction (Headlight control - Headlight aim control)
DTC
Description
No fault codes

Multifunction (Multi media interface - Diagnose)
DTC
Description
No fault codes

Multifunction (Parking assistance - Diagnose)
DTC
Description
00446
- Function limitation due to under-voltage
- Below lower regulation limit threshold
- Intermittent

Multifunction (Radio navigation system - Diagnose)
DTC
Description
U140000
- Function restriction due to insufficient voltage.
- Intermittent

Multifunction (Steering assistance - Diagnose)
DTC
Description
03803
- Steering angle sensor
- No symptom

- Permanent
Multifunction (Steering wheel electronics - Diagnose)
DTC
Description
No fault codes

and after deletion of codes with the two battery's still linked i checked voltage 12.18 and the exact same DTC'S i mean Exact same were logged after cranking it so i mean its even poor problem solving either way on my behalf because the very first thing i should have done was put a brand new battery into the car whatsoever ill do that this morning and put back the relay thats missing for heated rear screen and once again see whats going to come back to me DTC'S wise. iI wouldnt be surprised if it just fired up tbh with new battery
(WISHFUL THINKING) hahahaha

nearly there either way be sorted before Wednesday

 

[McCabe]

Nearly there....

Update, put back the missing 373 relay and also replaced the battery, was told that its a different start stop style battery i needed by the motor factors after recycling my old battery for me. they told me that the car would not perform properly with just a regular battery in. car started up first turn of the key no faults whatsoever. i still have got no heater blower from my vents inside the car, its lighting up and working on the screen, temp, fan speed, position of vents etc etc .... 40 amp fuse in dash is fine anybody and direction for me to go? I also checked the alternator after new battery went in with the car running 12.6 and 12.8 my highest reading. checked the power at the plug to the alternator and its bouncing around 6.7v 8.4v 9.6v 9.8v. wonder why i dont have 12v at the plug maybe the alternator isnt shot just yet. it would be brilliant if anyone had a wiring diagram to know where the alternator wire goes too so i can check for continuity and resistance on the wire....... but what would cause the voltage to bounce around ????? havent come across that before????

 

[Speed-FReek]

I can get you a wiring diagram later but you might have to wait until I'm home from work.

You should be getting around 14v with the engine running which should be a fairly stable voltage. What voltage do you get if you put your meter directly across the battery terminals while the engine is running?

 

[McCabe]

Yeah that would be great thanks very much!! I only have 12.6 or 12.8 at the battery whilst car is running and same at the alternator whilst running I checked the plug on the alternator and where I believe it should be a straight 12 v plug the voltage is bouncing around but does the BCM pulse the sterna tor upon startup I didn't check the plug off the alternator with car running must do that actually. But yes please speed freak that would be brilliant if you Coul d get your hands on a diagram just wanna make sure that the plug wire for alternator is OK see where it is going. Thanks

 

[csx]

battery

Well done so far - sounds like you have it nearly done.
I may be spouting rubbish here and Im sure someone will put me right.
When changing a stop start battery - the charging module needs to be told which battery is fitted.
New batterys come with a BCM - battery manufacturer and capacity code that needs to be programmed in by the dealer or vag com or such to tell the system how much charge it should deliver.In other words - It has its own hex address in the system. Another rip off system to make you buy the dealers batteries !
I believe you can buy them from motor factors - but make sure the code is with them.
Just a thought - maybe your issue .

 

[Speed-FReek]

Here you go. A wiring schematic for the Battery, Starter, Alternator, and Battery Monitor Control Unit on the CAYC engine which has the start/stop system fitted...

csx is quite correct in that you will need to code in the new battery. I'm not sure what diagnostics software you are using (the format looks like Delphi) and if it supports battery coding but the procedure for doing this if you were to use VCDS can be found on the following web page...

http://wiki.ross-tech.com/wiki/index.php/Battery_Replacement

 

[GordieC]

Regarding the blower not working, I've had mine stop before and it was simply a case of ducking under the glove box, removing a screw of two (can't remember exactly how many), twisting off the fan unit and freeing it up by hand.

I also applied a good bit of WD40 to dislodge any corrosion, ran it by connecting it directly to the battery (be careful doing this, it's got a good bit of torque and can easily jump out your hands while doing it so watch those fingers!), followed up again with a good bit of silicone grease spray, another run off the battery, wipe to remove excess grease and reinstalled.

I've had no issues with it since. I believe it's a fairly common issue with 1P Leons.