1999 s320 starting problem sometimes - PeachParts Mercedes-Benz Forum

RichardM98 · #1 07-31-2012, 08:50 AM

Quote:

Originally Posted by oldsinner111

smart key looks like a w126 key

Probably smart key is failing. There is a small coil at the front edge of the circuit board in the key. If the key is dropped and you lose good connection, you get intermittent recognition by DAS. New smart keys seem to be running in the $200-$300 range.

oldsinner111 · #2 07-31-2012, 08:54 AM

this key is 2 years old.How often to change batteries?

RichardM98 · #3 07-31-2012, 10:01 AM

I change mine once a year but batteries only provide keyless access. They aren't involved in starting the car.

oldsinner111 · #4 07-31-2012, 10:04 AM

will try cleaning ground to starter.I just hope its not the ignition switch.Lots of moola.

Gilly · #5 07-31-2012, 02:05 PM

A smart key looks generally like this, no blade goes in to the ignition, is this what you have really?

Gilly · #6 07-31-2012, 02:08 PM

Because I thought all the 140s used a switchblade-style key, generally like this:

oldsinner111 · #7 07-31-2012, 02:15 PM

its a w140 key,the dealer parts guy called it a smart key,he said the car had to know the key to start

glenmore · #8 08-02-2012, 11:56 AM

Quote:

Originally Posted by RichardM98

Probably smart key is failing. There is a small coil at the front edge of the circuit board in the key. If the key is dropped and you lose good connection, you get intermittent recognition by DAS. New smart keys seem to be running in the $200-$300 range.

My daughter has a failed Smartkey for her 1999 C280 and now has 2 new keys that still give her occasional start problems. I am going to open up the old key and see if there is anything obvious that I might be able to repair.

Anyone open up one of these keys? Do you just carefully pry it open?

oldsinner111 · #9 08-02-2012, 01:36 PM

I let the MB parts man change my batteries.

Gilly · #10 08-02-2012, 05:01 PM

Now the 99 C class I believe is a smart key, they didn't put it in the 140 chassis because they knew the replacement was going to be out in 2000 (W220), so they never did it.
On the smart key, the batteries have nothing to do with starting the car, as has been mentioned, only for the remote unlocking features. The car will start just fine with no batteries at all, just like any other car with a chip in the key for start enable.

Gilly

Gilly · #11 08-02-2012, 05:03 PM

Quote:

Originally Posted by glenmore

Anyone open up one of these keys? Do you just carefully pry it open?

Look where the the emergency blade slips in to the key, there is a small tab you puch in on to release the "guts" of the key, like to replace the battery. Push in with a small screwdriver. Again the battery doesn't matter.