sl500_dallas

2007 SL550

Okay guys. I have one for you that I can't find anything on after an exhaustive forum/google search.

Dreaded P0016 P0017 codes - CEL on, but would go off at times without reset and then come back on, then go back off, etc.which I thought was strange
Noted that the car was sluggish when I was starting it and getting worse to the point of almost not turning over at times, like a low battery
Connected charger - much stronger start up - CEL instantly turned off (I've repeated this step on several occasions now with the same results)
Charged overnight - Strong start up, increased performance, CEL remained off for quite a while
Went and had battery checked after charging - Car guy at parts store says battery shows good and alternator charging at approximately 13.5v. Battery is year 2014 OEM

Any ideas? Is this a battery issue? A charging issue? Or do I simply have the issue shown by the codes? I don't know what's going on here, but I don't think charging the battery should turn off the CEL unless there's something going on there. Any feedback is VERY much appreciated.

kbob999

Looks like a camshaft position sensor, or related issue.
Might want to research those sensors or replace.
Let us know what fixes it.

Rudeney

P0016/P0017 is not a problem with sensor, although as that video shows, removing them can help to verify that the camshaft adjusters are out of alignment. It's a problem with the timing chain idler sprocket wearing away which creates slack in the chain. The sprocket has to be replaced. On the V8, it is possible to do this without completely removing the engine as with the V6. On the V6, the engine must be pulled as the sprocket is a forged part of the balance shaft and it has to be removed which requires the engine being pulled out. Regardless, even without pulling the engine, it's a fairly involved job and you do have to lift the engine to remove the main oil pan. Dealers charge over $5K, an indy probably $3K-$4K. As a DIY, only tackle it if you are highly skilled.

This will have no involvement in the sluggish starting problem. In fact, it will have no effect on engine performance at all since the ECU can detect the actual camshaft position and compensate using the adjusters. It is normal for the MIL to sporadically illuminate as it begins to wear. After a while, once it wears enough, the MIL will illuminate constantly. There is not a huge sense of urgency for the repair as it takes a good while for the sprocket and chain to fail totally. I'm not saying you can drive another 50K miles like that, but it's not going to die tomorrow. The sluggish starting is likely a bad starter battery, relay, solenoid or starter itself. The starter on my SL550 went out and it began to act sluggish, like a weak battery, about a month before it died.

kbob999

Rodney,
Thanks for the informative post. You are the master Obi-wan! I had a feeling this was related to the chain and sprockets.
Dallas - looks like it's time to dig into the wallet or sell cheap. Sorry to see this.

moretech

sl 500 dallas. WOW this is not the kind of problem I like to think can happen to a Mercedes engine. How many miles on it?

moretec

sl500_dallas

120k. Apparently, it's a pretty common issue. There was a class action lawsuit.

Rudeney

Actually, it's not very common. There are were about 500,000 M272 V6 and M273 V8 engines that fall within the range for potential premature failure. Basically, most all non-AMG V6 and V8 MBZ's made for MY2006 and half of MY2007. But only a small percentage actually fail prematurely. It's not even enough to show as a blip up on any of the consumer review forums (Consumer Reports, Edmunds, etc.). Note that I used the word "prematurely" because these are moving parts that will wear over time and eventually fail. In fact, most engines will need timing chain parts replaced by 300K miles.

Here's a TSB with the details about the engine numbers and such:

http://benzbits.com/BalanceShaftTSB.pdf

Some engines failed very early, while still in warranty, and were repaired. Others, like my CLK550's, failed at 30K miles, but some months beyond the warranty, and MBUSA fixed it under "goodwill". The problem with the MBZ sprocket seems to be that it was improperly forged by the supplier and was thus too soft. Apparently, the defect is not known "per engine" but only for the range of engines built until it was discovered. Speculation is that the supplier had a defective furnace that did not always reach proper temps when head hardening the parts. Most of these parts were properly hardened, but some were not hardened at all, and others are somewhere in-between.

The class-action suit really didn't help many people. By the time it was approved, it only covered engines that had already failed and the owner had paid to have it repaired. For those, they got a refund of costs. For others that failed later, they got nothing. Legally, MBZ offers a warranty and for failures within that, they pay to fix the car, and after that, the customer pays. If this were a $200 fix, then it never would have gone to court, but because it was a $4K+ repair on expensive cars, some people decided to sue. I think in legal terms, the suit really had no merit, but some judge felt otherwise. Having said that, I do believe that MBZ mishandled this. IMHO, they should have acknowledged the issue and given owners an extended warranty to cover the failure.

moretech

Thanks to all above on this thread for the info. Very informative, making our forum work for all of us.

moretch