Car tried to start itself and kept cranking without ignition key / key was home in a drawer

[Maxlibertas]

Well, everything is unprecedented until it happens for the first time. 2010 golf highline 122 tai dsg with sunroof 48000km.


The other day it was raining and I was sitting home and heard a car failing to start, cranking continuously, thinking it was a neighbours, ignored first. When it kept going for about 10 mins, I got out to offer help then realised it was my car cranking. In shock, went upstairs and fetched the key, got into the car. Engine was cranking and all lights in the dashboard was flashing in a natural fashion seen when the car started. Battery must have been draining, I caught a glimpse of a faded message "key not found". After inserting the key in and turning it few times enigine eventually started, all normal, no warning lights or messages. Turned the switch off but engine kept running, tried again the same, took the key off the switch, the same. Went home to fetch the phone returned to car, gave it a try, this time I managed to stop the engine. Turned the key to on position, a bulb indicator appeared with accompanied with " check front turning light " message. Went inside and noticed hazard lights were flashing, I disconnected the battery. Rang up vw dealer service, adviser suggested to reconnect the battery and if same thing happens record a video of the thing. Rang up a technician who used to be master technician at this dealer and opened a private service, he suggested possible water leak into BCM (body control module) or faulty ignition switch, better have the car towed to his garage for investigation. He mentioned it's not safe to drive, things may get worse. He also mentioned sunroof draining pipes need to be looked at for possible cause.

Few weeks back I had a similar bulb imessages. All bulbs were in working order but various bulb messages kept appearing. Few times I noticed hazard lights were on when coming out of supermarket. On start of the car flashing would stop but a red light on hazard warning switch would blink. All those happened on rainy days. Spoke to a technician, a body control unit would cause this and has to be looked at. Weather was fine past couple of weeks and nothing strange happened, I didn't drive 70 miles to go to the garage.

It iwasn't raining yesterday and I did take a quick look. Removed the rubber mat and discovered the trim underneath was soaking wet on drivers footwell. (LHD car). Passanger side didn't look that bad. Rear passanger side footwell was also damp but this was known for sometime and was ignored. I also noticed some white stains under the dashboard around knee area, a possible cover for BCM. I am also aware inside the windscreen gets dump very often and windscreen washer liquid smells inside the car when utilised.

I tried to investigate the leak, everything seemed ok under the dashboard and bonnet to naked eye. Noticed a wet area on the the bottom of windscreen around the wipers cover, windscreen didn't have a seal but seemed joined with a sealant , when pressed to the trim, water would come out of it.

Car is going to be towed to garage on Monday. Trims would be removed to dry out, causes of the leak will be investigated etc. , then I would know the damage and £££.

Would it be possible for water to reach to ignition switch and cause a hot wire ? Failing to turn off the car makes me think so.

On march'17 I had a surgery to remove a tumour on my left shin, was on my feet again on august'17 and on September'17 I opened the door of a neighbour's car door to look for a lighter, the car rolled backward fast and dragged me along eventually running over me, breaking the same left shin badly. I am still recovering. Since then, stationary cars are mysterious to me. In that case i, car was parked on incline in gear, handbrake off, some 200kg worth of earth for gardening in the boot, when I opened the door weight balance was disturbed, front wheels lifted and car rolled back fast.

I will keep you posted, meanwhile I would appreciate what anyone think?

[Maxlibertas]

I replicated the problem today. Reconnected battery, bulb warning, steering wheel, esp yellow warnings on the dash. Started up, no issues engine running fine, moved forward backwards few times, it drives. All warning lights disappeared, except rear wiper working uncommanded and unresponsive to command. Tried operate front windscreen washer, unresponsive. Pushed the wiper stalk down to operate, made funny noises and engine tried to start while engine running. Switched off the ignition but it fired immediately, switched off the engine, disconnected the battery. Seems a bigger problem than I initially thought.

[Keithuk]

Have you fitted LED bulbs as that will bring up the bulb warning. You can Google this they fit a resistor in the circuit.

Front wiper not working could be a faulty Bonnet/Hood Switch (F266) Bonnet Contact Switch (F266). Check all fuses if you have a fuse and relay layout.

You need to get your motor scanned (preferably with VAG-COM\VCDS) for any error codes logged in the ecu and post them, that will save a lot of guessing and check systems out.

The rear washer not working is a common fault, you need to check the pipe hasn't split and so the water goes into the boot.

[Maxlibertas]

Thanks Keith.
Vehicle is unmodified, OEM. Everything was in working order until the starter motor engaged without command. Technician thinks faulty bcm due to water getting into it. My concern is now started motor engaged today while the engine is running, hoping it didn't cause any further damage to engine et al as it made funny mechanical noises, i disengaged immediately.

Car is going to be towed away tomorrow for diagnostics.

[Crasher]

Yes I would agree, faulty central electrics unit. I had to change one on a Passat a few weeks ago just because the washer motor pump was drawing excessive current and it burnt out the solid state relay, £650 to repair your washers!

What has happened to you is VERY worrying, that could easily cause car, property damage, injury or even a fire if it were left in gear, I have never heard of it before and I hope for VW’s sake it is a one off or that could turn into an expensive safety recall.

[Maxlibertas]

Thanks Crasher, I am indeed VERY worried as a stationary car rolled back fast upon opening the door and broke my leg, plate from knee to ankle, 13 screws, still having PT.

There is a lot say on VW side, cabin expected to be designed and built weather proof, and such critical part to safety should have been waterproof too. Car is out of 2 years warranty , 7 years good will period, I don't expect the dealer contribute to repair, going private.

Possibly there is a short circuit somewhere as starter motor requires high current. Pushing down the wiper stalk initiated circuit and it seems miscommunication between modules as engine was running already when starter motor engaged without command.

What i know so far is drivers footwell is soaking wet and there is a resident stray cat under the bonnet.

[Crasher]

The ignition switch output is converted to a digital CAN BUS signal by the steering column control box and this “line 50” signal is transmitted by wires to the J519 Central Electrics/Body Control Module which then takes this signal and sends a reasonably high current signal to the stater solenoid which when energised gives the motor its heavy duty power feed. This signal should not be sent by the J519 without the ignition being on, known as the “line 15” signal so it would be interesting to study the measuring blocks of the relevant control boxes. Where the leak is concerned, well ALL cars can leak, it is one of those things and is not confined to VAG products.

[Maxlibertas]

Thanks Crasher for the technical explanation, "signal not being sent by J519 without the ignition being on" makes me to speculate somehow something happened in steering column control box, may be water made its way to there as on first occurrence the key was in a drawer. It would be interesting to see the measuring blocks.

Spoke to official VW helpline, technician first asked if the car had a sunroof then pointed central electrics unit. They are happy to send a tow track free of charge providing that the work is carried out by themselves. He knew the technician I intended to go but left it to my preference.

The car has been serviced by official dealer past 8 years, turbo changed at 8000km with suspicion of wastegate control rod being stuck, at 11000km dsg double clutch changed for the fortified version, dsg fortified version double clutched replaced again at 18000km, on both occasions I didn't have any symptoms, didn't feel a thing. Warranty covered all expenses. Tyres were changed at 6th year, replaced the battery 2 years back, water pump was replaced last summer due to a ticking noise, car mostly has been trouble free until now.

[Crasher]

Looking at the diagram, line 50 on the 4mmCSA red wire comes from the J682 terminal 50 supply relay which is commanded by the J519 onboard supply control unit (BCM) and is supplied by fuse 7 (40amp) in the under bonnet E-box on the upper fuses know as SB so fuse SB7. SB7 is fed on what is known as the 508 line which is unfused and permanently live. There are a number of VIN and spec variations over the J682 relay so sending me your VIN or reg would help. The J519 relay is commanded by the J519 on a 0.35mmCSA red/black wire so if there is a feed on the terminal 86 of the J882 relay, the error is coming from the J519, but why?

[Maxlibertas]

Thanks again Crasher, VIN is WVWZZZ1KZAW233650. Part number for BCM is: 1KO 937 086C. Thank you very much for you time and thoughts on this, your post is beyond my technical understanding. I am also very curious to find out what happened, I hope you might be able to shed some light. The technician thinks a soaking wet bcm unit could do this, it controls everything, but doesn't think beyond that.

I went with the tow truck. Technician finger pointed the leak in a minute. Removed the A pillar trim and sunroof drain pipe was dislocated from the joint at the bottom end of A pillar. He dismantled the BCM, nearly a glass full of water poured down from the box. Circuit seemed undamaged on both sides with some minor corrosion. He sprayed something on the circuit and dried it out. There was another unit with same part number, second hand, he didn't know what was wrong with it. This unit was installed, the car started, no issues except rear fog light stayed permanently on and near side drl permanently off. Original unit dried and was installed back. Everything in working order. ODIS scan was flooded with spurious messages, mostly about the lights, one fault remained ( I don't what, will clarify later on) , he said he erased it but may occur again, he will look into it.

All sunroof drain pipes will be inspected and rectified and checked. Some specialists will be called to dry out the floor pan trim and insulation, I may expect to pick up the car few days later. I didn't ask about the cost, I will be paying for labour in this case which is well deserved, he seems a decent guy.