I have a 98 ML320 65,000 miles. Was running great parked it next day wont start??? Turn key cranks about 5 secs then turns off. I replaced the PCS sensor like evry body sug. but same propblem???? What else can I look for?? I dont smell any gas fumes but tank full. THANKS

Can you pull a plug to see if gas is getting to cylinder?

Connect a generic code reader and see what comes up if anything.

You make reference to PCS sensor, do you mean crankshaft position sensor?

That sounds like a security problem. It is not recognizing your ignition key. If you have another key, try it first. You may have to have Mercedes reprogram the AAM to accept/recognize your key.

It is not known what can wipe this memory all of a sudden from your AAM. Jump starting is one thought that I have. Also, an old or weak battery may do it. Maybe a close lightning strike can do it! Who really knows?

AS you put your key into the slot, watch for the little red LED to flash, which indicates it has recognized your key. You may have to wait until dark to check this as these LEDs get weaker with age. Where is the LED you say? A couple inches to the right of the key switch on the center console.

Good luck,

Jim in Phoenix

Thanks Jim I Will Try That. I Did Almost Ask Where The Light Was Til I Read On Lol Can I Check Spark Some How. The Old Days Pull A Plug And Crank Over?? How Do I Pull The Plugs Any Special Tools I Need? Thanks

Thanks Ron Yes The Crank Position Sensor I Replaced Was Easy Just Strange Was Running Great Then Nothing I Did Try Another Key Same Thing Cranks Not Starting.

Same just like my 98 ML.
I order a new key from mercedes and reprogram (now start and run).