2003 Mercedes Benz clk amg55 doa
Towed in, car does not respond to buttons on key fob. key fob does not rotate in the ignition slot. Car seems almost completely dead. Park lights seem to be the only thing working. Battery tested, soc & soh acceptable. No comms with our scantools. Not really familiar with these vehicles, but customer wants us to get it working again. My research shows the eis (key/ignition) module is supposed to wake everything up, check power and ground to eis module ok. Scope Interior bus, 12v on can low and 2v on can high. No activity on bus. Check engine bus at eis module and 0v on both wires. Locate all 3 interior bus splice packs and find passenger side has some corrosion and there is water ingress on that side of vehicle.
Took a step back and had to think for a while. Front Sam is mostly dead, only about ½ a dozen fuses are alive in there, again traces of water ingress here too. Found 2 main relays in Sam and jumped power to them, now interior bus is back online and looking like it's supposed to. Supplied external power to pcm and now engine bus is active as well. I can now communicate with pcm, but still not with eis or front Sam module. There is a wire in dlc connector that goes directly to eis module, scope that while trying to communicate on scan tool, no response from module.
Question: do I have dead eis module or faulty key or something else entirely? How do I diagnose this?
Usually with the hazards on you can get the scan tool to communicate. Then go into the eis module and look at “drive authorization” it will tell you if the ignition is allowing it to start as well as engine and transmission. In order for ignition to turn it needs to see a good key. You likely have a bad ke or ignition.
You need two keys to get started. Any car should have two keys. If the new key doesn't fix it you still have a second key, which is of value. If you guess wrong and replace the EIS, the second EIS doesn't do your customer any good. If customer balks at buying a second key, boot him out.
This morning turned on hazards and tried scantool on it to see if there is any response, nada zip nuthin. Got another eis coming. Fingers crossed.thanks
Update: received a used eis today, plugged it in, scantool communication restored 😊 so this proves that old eis is dead. Interior bus is back online, key does not rotate. But I assume that is because this module is one use only/vinlocked. New eis ordered. Thanks.
I had this type problem on these cars three times number one their is a 5 amp fuse that blows on the alarm audio that causes the switch not to turn on. I have disconnected the the audio speaker and replace the fuse and fix the problem. The other two time is was the ignition switch defective. The steering lock module can short out and cause switch to fail. Ether way no key authorization . check…
Good information, I will check that before plugging in new eis module. Thanks.
Which location are you connecting your scan tool? The main diagnostic port is under the hood on the right side, inside a plastic compartment.
I am using 16 pin obd connector under dash. The diagrams don't show another diagnostic connector, also had look under hood, don't see anything there? Maybe on a different year or market ? thanks.
2003 clk (W209) should only have a 16 pin obd2 connector, no 38 pin under hood. You should be able to connect with the EIS with the key out of the ignition. When you order a new EIS from MB dealer you also need to order a special loaner key that you insert in ignition to code EIS to car. In the U.S. MB Considers EIS a Theft Relevant Part (TRP) so you usually have to provide dealer with…
My mistake, you're right, there is only the 16 pin under the dash on a 209.