Won't start: Lock / Unlock to reset computer?
 

99 ML 320 with about 175K miles. Wife called and said it would turn over but not fire. I had her call roadside assistance first. They told her to get out of the truck, lock it with the remote, unlock it, and then try to start it again. They said that would reset the computer. Well, it worked.

Now, what should I worry about? Should there be a code to explain this malfunction? Do you think I should have a professional go over the truck to see if they can find anything?

Thanks in advance.

on ML's the locking system doesn't inhibit starter motor operation. If the starter works the but the car won't start, it isn't related...I would think you are starting to have either a crank sensor problem OR a fuel pump problem.

Well, it happened again today. Same scenario. Except this time it still wouldn't start after lock/unlock try # 1. She tried two more times and called me. I told her to wait a few minutes and try again. She did and it started.

No CEL. I asked her to get the codes read at Autozone after the first episode. She never did.

So now she is on her way directly to our favorite indy mechanic.

Update: Phone rang while I was typing. Mechanic says 90% sure it's crank position sensor. $226.87. I told him to go for it.

Its a US$70 part (retail) and about 30 minutes work to replace it.

Did he kiss you and promise to still love you afterwards?

Have your wife carry the second key with her, if it does it again see if the other key will start it.
Gilly

Well, my wife handled this so I'll have to ask her. :pirate:

I would have done it myself but:
1) local dealer, Dick Dyer Mercedes, sells it for $148.50. Their parts prices are usually outrageous so I buy as little as possible from them. In light of the local dealer's price, $226 sounds reasonable.

2) would have gone on line to get it but timing is not good. I'm working 12 hour days, we have a young child, we're traveling this weekend, blah, blah, blah.

3) I just tried to check online prices for the heck of it. Fastlane and *************** are out of stock. Two other sites say call them so I suspect they are out as well.

Good idea. Will do. (But I hope the new CPS fixed it.)

Thanks Gilly.

Try Steve Schock at: http://www.europarts-sd.com/ He's where I get most parts that don't have to come from Europe.

Thanks! Bookmaked for future reference.

I'm sure that it will.

FWIW, the CPS is available as a non-MB branded Bosch part for a whole lot less than the dealer would charge you for the branded part.

In regards to the key being a possiblity, if that IS the cause of the problem, when the engine is cranking but not starting, the odometer display spells out the words "start error". That's where she'd want to try the other key. It means the key which isn't allowing the start has a bad transponder "chip" in it, not too uncommon. That's about the only reason you'd get that display (it could be another type of DAS problem tho), it means there is a problem with DAS (driver authorization system), it won't show this for a problem like the CPS or a bad fuel pump for example, this is very specific to a problem with DAS.
Gilly

CPS Evaluation
 

I've started a thread on how to evaluate the CPS at Benzworld. Here's the link:

http://www.benzworld.org/forums/w163-m-class/1282808-cps-evaluation.html?highlight=cps+evaluation

Here part of the post:

The following is my opinion and I welcome any comments and suggestions. I'm posting this because I am getting the impression that many people point to the CPS as a problem when their vehicle doesn't start or stalls. Even though this area is a potentional cause for no starts or stalling one should not assume that it is the only reason and many replace a perfectly good sennsor for no other reason than to hope that it solves their problem. The CPS can fail for many reasons and they do fail. Heat can be an cause for CPS failiure (I've tested one on a bench with a torch applied to it and measure the effects of heat on it's resistance and there is a noticable change.) but it can also be flywheel damage, debris on sensor, installation, etc. The only definitive way to rule out the CPS is testing which is not difficult. Measuring the resistance is a poor test which is too general. The best way to test is to use a scope (oscilloscope) to observe the waveform and output. Please see the attached image from a W126 WIS. On this application, the output (Us) must be greater than 1 volt. If the computer does not see this minimum requirement then it won't know when to time the car! I do not have the W163 WIS so I cannot compare the differences but the concept should be the same.

Comments?

DL

Things like workman's comp, liability insurance, and monthly lease/mortgage payment don't come cheap. Then there are security, uniforms, advertising, shop supplies, shop equipment, mechanics salary, and the list goes on, not to mention, he has to warranty the repair job.

I don't know very many wealthy shop owners, the overhead is very high and they make a honorable living by the virtue of hard work. More than I can say for pencil and paper pushers.

Bump..