SL500 (R129) - Cut out & will not start

[Banjo]

Hi all

I have a problem with my 2001 SL500 Silver Arrow and would appreciate any help.

I was driving along (straight road) around 35mph, the steering stiffened and all the instrument cluster panel lights came on. I thought the car had stalled (has never stalled in 4 years of ownership), put the car in neutral, turned the key (still coasting) - ignition came on with all lights, turned to crank position and no response. Tried again - nothing. Coasted around the corner and stopped. Put the car in 'P', switched on ignition (all the lights came on), turned to crank - no response.

A few details.

1. All electrics work. With the ignition on - all lights work, car locks/unlocks via remote (immob light comes on and of), heater works, radio works etc.

2. Turn ignition on and no sound from fuel pump. However if it was the fuel pump as a problem I would expect the engine to still crank and not fire - engine does not crank.

3. When you turn the key to the cranking/starting position there is no response at all. Zero. There is no click. The instrument panel lights do not dim as you turn the key. This leads me to think there may be a problem with the ignition switch. However,

4. The car cut out whilst driving leading me to believe that there was an instant failure of some electrical component/relay.

Any ideas and suggestions would be very much appreciated.

 

[IanA2]

I'm not terribly technical but someone who is will be along shortly. That said it might be the transponder thingy that fits on the ignition key assembly, a common fault, not hugely expensive, I think about £50 plus half hour fitting.

A more techie sort will be along soon I'm sure.

 

[BTB 500]

Crank position sensor perhaps? Also relatively minor.

Could be all sorts of things really, need to get it to a garage and have the fault codes read.

 

[Banjo]

Many thanks for the prompt responses guys. I broke down quite late last night and RAC flatbedded it home for me.

I aim to get it to the garage and get the codes read and the wiring checked underneath.

Ian, the transponder that you are referring to, does that sit on the ignition barrel and read the chip in the key block? or is it the one in the key block itself?

 

[IanA2]

Many thanks for the prompt responses guys. I broke down quite late last night and RAC flatbedded it home for me.

I aim to get it to the garage and get the codes read and the wiring checked underneath.

Ian, the transponder that you are referring to, does that sit on the ignition barrel and read the chip in the key block? or is it the one in the key block itself?

It's the sit on one methinks...

 

[stats007]

Sounds like one of the two things suggested already.

HowTo for the ignition switch problem on an earlier car.

 

[EDZ649]

I had a very similar problem a few weeks ago on my SL600. Almost identical symptoms. It turned out to be the wiring between the ignition switch and the starter relay. It was a bit of a pig as half the dash had to come out to get to it, eight hours labour in total! Good luck with yours.

 

[Banjo]

Sounds like one of the two things suggested already.

HowTo for the ignition switch problem on an earlier car.

Thank you! That is very useful.

I had a very similar problem a few weeks ago on my SL600. Almost identical symptoms. It turned out to be the wiring between the ignition switch and the starter relay. It was a bit of a pig as half the dash had to come out to get to it, eight hours labour in total! Good luck with yours.

That is really interesting as my Dad seems to think that the problem may lie with the wiring to the starter! Did yours just cut out whilst driving also?

I haven't had a chance to get the car to the garage as yet as I am too busy at work, but will certainly let you know what we find.

I really appreciate your input guys, any light on the problem is certainly a great help.

 

[EDZ649]

No, mine didn't cut out whilst being driven, I drove down to a local tyre place to get a new tyre fitted and when I went to start it afterwards it wouldn't crank. Had all the dash lights up just the same as yours. I ended up getting it taken to the dealer. The tech who sorted it spent 8 hours but they only charged me for 5, must have felt sorry for me! Be interested to know how you get on, Leigh.

 

[IanBushell]

Sudden cut out problem

Engine earth strap? Have heard it can be a problem on 129s

 

[C43AMG]

Engine earth strap? Have heard it can be a problem on 129s

That happened to the C43.

 

[Banjo]

It could be an earth strap. Preliminary inspection of the engine bay shows the earth straps to be intact. But TBH there is only so much you can see and there is still a possibility a strap underneath could have broken.

My niece reckons that as the car does not get driven very much, mutant squirrels have decided to make it there home and I must have disturbed their sleep with my late night cruise!

I have booked the car in with the garage, the only problem is that it will be 25th May as I am away on holiday until then. I wil definately let you know what we find.

Once again I am very grateful for the help and information guys, this is not a problem I have experienced before and it is very perplexing.

Many thanks.

 

[DSLiverpool]

Immobiliser ? all evidence points to one failing

 

[stats007]

It'll be the ignition switch.

 

[EDZ649]

Any progress on this yet?

 

[Dieselman]

It'll be the ignition switch.

I'll go with that or the main engine ECU relay given that it happened when you were driving along, not when just trying to start.

I was driving along (straight road) around 35mph, the steering stiffened and all the instrument cluster panel lights came on. I thought the car had stalled

 

[Banjo]

Update

Hi guys

I finally managed to get the car flatbedded to the garage on Weds. On initial diagnosis there was no power going to the starter motor from the ignition (direct feed showed the starter is functioning). So we replaced the starter relay (£8) but no joy. Today the ignition switch (electrical part) has been replaced, unfortunately the problem is still present. I am not sure what the next step is as yet...

best

 

[stats007]

Is DAS working?

 

[Banjo]

Das?

 

[Mercedes cozy]

These cars have a common fault. I put my money on the Ignition switch attacted to the steering lock.

I had the same problem a few years back when I had one.

After changing the ignition switch the car was back to normal and never cut out while driving.

I open the old ignition swith made out of plastic only to find that the contacts were worn inside.

Get a new ignition switch and put it on, Should take no more than 30 minutes to install. Common fault.