W204 Won't Start

[Judwin]

Got back to Heathrow yesterday after a 26 hour flight, and last thing I needed - car wouldn't start.

Salient facts...
1) W204 C180 Petrol, Manual, Estate/Wagon,
2) Car unlocked normally using the remote controlled Fob/Key. Boot hatch opened for me to put luggage in the boot.
3) Inserted key into ignition switch - radio turned on normally, and dashboard lit up normally.
4) Turned key to start/cranking position, and nothing. No cranking at all, no dimming of interior or external lighting, no interruption of radio.
5) Repeated 4 several times, and turned off various electrical bits and bobs trying to work out if it was 'just a flat battery'.
6) After perhaps 10 attempts the car started. Uneventfull drive home.
7) Stopped at local corner shop 5 mins from home to get some milk. Car wouldn't start again. Same symptoms.
8) After perhaps 5-10 key turns, just as I was getting ready to bump start it, it started.
9) Got the other key from home and so far today, it's started first time every time.

So I've ruled out a flat car battery - there is no cranking whatsoever, and the headlights don't dim. So whatever is supposed to be telling the starter motor to turn, isn't. And it can't be the auto gearbox starter interlock coz its a manual.

It could be a flakey ignition switch, or a starter motor solenoid on the way out, or I guess a relay in the solonoid drive.

Or it could be the first key itself. There was enough juice in the keyfob battery to work the remote lock/unlock and boot stuff - does the ignition require the battery in the key to be servicable for the transponder to work?

Any other ideas what to look for? I've a couple of other airport trips in the next few months and being stuck in the carpark on return doesn't add to the enjoyment.
Cheers
Judwin

 

[Blobcat]

Ignition doesn’t need the key fob batter at all - inductive loop in the binnacle that powers the chip in the key.
Sounds a bit like failed drive authentication. EIS switch failing - does the steering lock release?

 

[Judwin]

Ok, Thanks, so almost certainly not the battery in the key then.

I don't know if the steering lock released or not - I didn't know it was involved. I do remember as I was preparing to try and bump start it by pushing the car to another position thinking "flip me this steering is heavy" but without PAS assumed it was just that. Didn't feel like a hard steering lock to me. I only pushed the car about a yard before trying the key one more time, and the car started. I wouldn't have considered trying to bump start without first checking the steering lock was off.

If/when it happens again I'll remember to check. But more importantly, is there a way to get the car to start with the steering lock failed? I realise its probably a security issue, but I just don't fancy being stuck in an airport car park at midnight with a car that won't start.

 

[star]

In position 2, do the ign light come on in the dash? If not, more likely to be esl.

 

[Judwin]

In position 2, do the ign light come on in the dash? If not, more likely to be esl.

Not sure what you mean by position 2.

I put the key in the ignition, and turned it one click. All the dash lights came on properly (as far as I remember anyway). Radio came on, external lights came on everything 'normal' AFAIK.

Turned the key further to start the car, and nothing happened - the starter motor didn't turn. The symbols on the dash remained the same.

I'll specifically check for the ign light if it happens again.

 

[alcmackew]

Sounds like the keys not recognised by the ignition so won't start the car. Have also heard the steering locks can fail to release on this model which would also not allow the car to start.

 

[Judwin]

Had a bit of a play this morning whilst it's working to see what should happen so I can tell what isn't happening if there is a next time. I now see what star means by position 2 (I think)

Inserting the key into the slot in the dash (but not turning it) causes a whirring noise which lasts perhaps half a second. Pulling the key out again produces the same whirring noise again about half a second. I assume this is the ignition steering lock coming on and off.

Turning the key to the first click brings the radio on.
Turning the key to the second click brings the dash on, complete with all the warning telltales.

I hadn't realised there were two distinct clicks on the ignition barrel because you basically just shoot through them both when starting the car.

Turning the key past the second click (against the spring loaded return) turns the starter motor. There is a temporary dimming of dash lights whilst the engine starts - perhaps a tenth of a second - barely noticeable unless you're looking for it.

Both keys are working at the moment, so can't do much more till the fault returns, which sods law says will be at the most inconvenient time.

 

[Judwin]

Did it again this morning. Stopped on my way to work to get my lunchtime sandwich, and it wouldn't start on coming out of the shop.

The steering lock is releasing - mechanically at least. However that doesn't necceserrily mean the sensor is working I suppose.

As far as I can tell, all the dash/ignition lights are correct - but the starter motor doesn't turn when the kew is moved to position 3.

After fannying about for 5 minutes it did eventually start. I can see this is going to get annoying.

 

[alcmackew]

I reckon its the key - intermittently recognising and then not - does your spare key also have issues like this?

I had a problem with an old holden that turned out to be a rubber cover I put over the key - is your key covered with anything like a rubber protector or similar?

 

[DSK]

Have any codes been read?

Fwiw my w221 is stranded since Sunday with the identical issue. Only failed to start a few times in comparison to yours, did a motorway trip without issue and not started since.

Based on how it’s got to this, both keys ok, no obvious codes originally and will see if garage reads them again now that it’s happened since and been stranded, I think starter motor. Just funny how it happen on the way home from a service.

I hope you get yours looked at and sorted before it leaves you in a mess.


Sent from my iPhone using Tapatalk

 

[Judwin]

I reckon its the key - intermittently recognising and then not - does your spare key also have issues like this?

I had a problem with an old holden that turned out to be a rubber cover I put over the key - is your key covered with anything like a rubber protector or similar?

Has now done it with both keys. First 3 times were with my #2 key, but Wednesday was on #1 key. Both keys are 'naked' no covers or other fluff on them.

Have ordered a spare 'green' relay and will put that in when it arrives. There is an interesting French YouTube video showing how to get it started even if it's the steering lock that has failed (which I don't think it is in this case).

At the moment I'm dying of (an expected to be fatal dose of) Australian Manflu. If by some miracle I survive I'll plug the Scan Tool in and see what I can find.