Our W140 S500 cranks but will not start and the central locking will not respond to the remote. Is the problem with the ignition module? Any advic will be appreciated.
Hello and welcome,, the fault will be the the immobilizer is on if the remote locking is not working,,your should be the flip out key,,hold it in front of a digital camera and see if you can see the beam
Thanks for that. We have 2 new remotes and the car doesn't respond to either. I have tried the digital camera trick and they are both working. Thank you for your confirmation.
As the problem was affecting both the remotes and the starting I thought it could be the Anti Theft Alarm module which I understand to be located under the rear seat. I believe it also isolates the fuel pump hence the non statring. Is this correct?
We have had this car for a couple of years and it has been running well, regularly serviced and driven most days. It is a 1994 model and done 220,000 kms.
Sorry for taking so long to get back. I am waiting to get the car back. The roadside assist people took it to an auto electrician who had the ECU tested and says it is faulty. I will get the car home on Monday and will try the resync process. Iwill let you know how it goes. I just hope that more damage has not been done testing the ECU.
IF the ECU is faulty then you will have to buy a new one from mercedes as it will be coded to the chassis.
Your car needs star diagnostics before you do anything else to see whats actually going on.
That is an interesting comment. I was not aware that the 140 was any different to other models. I have had this situation with other vehicles and have just replaced the ECU sometimes directly from Mercedes and sometimes from Bosch. I have also used second hand ECU's.
To follow up with the problem with the remote. Once the ECU is unplugged the remote workes fine but not when it is connected.
I will need to check with Mercedes Australia re needing a coded ECU. Thanks for the heads up.
Once again sorry for taking so long to get back.
I have just received a new ECU from a dealer in Japan, there were no new ones in Australia, bolted it in and the car started first turn of the key.
The myth that they are coded to the chassis is just that, a myth.
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