pmesc

Have a 1997 E420 with 150K miles. In last 2 months, has developed an intermittent issue at attempted startup. I turn key to on, dash lights up, and Check Engine Light is flashing (not on solid - flashing). Engine will crank, but will not catch. If I go away and come back later, eventually it will start. "Later" can be anything from 4 hours to 3 days (in the case of 3 days, I checked 2X each day). Have had it to both local mechanic and dealership - the computers show no codes whatsoever. Of course, it was running when I went there, so they couldn't replicate the moment of failure.


Has only occurred on a cool engine. I live in Arizona, so hasn't been a "cold" engine. But has never occurred when engine was still warm from driving.


Looking for any wisdom. I've seen several blog posts of similar issues, but none of them ever posted a solution. Help?

Plutoe

I doubt this will help, except for the understanding of the starting circuit---you 97 like my 99 are diagnosed with the MB HHT built into the DAS Xentry systems.The bad news is that unlike the W211 there is no diagnosis of the starting system per say therefore you will not get a CEL for any fault because the only fault reporting control module is the key module.

The other important issue is that depending upon MY date MB placed a starter relay on the K40 board starting circuit, so you know by VIN or a WAG and rip the K40 apart to find the relay and check.

You also have the gear selector switch in the starting circuit--that could be an issue

So you have the key module, fuses, posible relay, gear selector switch and starter to check out-----not easy to say the least especially when one of the components has not failed!!