Mercedes-Benz issues 'do not drive' order for 300,000 SUVs; Hyundai alerts steering column issue

“Mercedes went so far as to issue a “do not drive” order for SUVs made between 2006 and 2012, urging owners to have their vehicles towed to the nearest dealership due to a problem with the potential accumulation of moisture and corrosion in the brake booster housing unit, which can impede brake performance and cause possible failure.”

Wondering how does moisture get into the brake booster, since it is under the hood.

I notice there’s a Dodge recall for an egr valve that sticks open, prevents the engine from developing proper power. It seems like the egr system (on all cars, not just Dodges) has been problematic ever since it was invented. It can fail in a nearly uncountable number of ways. Wondering, is there a reason why an alternative more robust scheme to control combustion temperatures isn’t used to replace yesterday-technology EGR systems? Or is there just simply no better system available?

I think the moisture is condensation.

MB will fix the problem at their expense, but who will foot the bill for replacement vehicles while the grounded SUVs sit waiting for parts? We all know the owner will have to foot that bill. I bet a lot of owners will continue to drive their SUVs until the parts come it.

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Not sure why, but it seems a lot of the newer vehicles do not have an egr valve anymore. My 2005 Sierra does not, but some earlier versions with the same engine did have an egr valve. Maybe the exhaust has less unburned fuel in it than it did previously? Better / more efficient computer control of the fuel injection in the later models? It seems like GM dropped the egr valve on those motors at about the same time they went to drive by wire vs drive by cable…. I don’t know, but now I’ve started thinking about it :thinking:.

At least I will never have to replace an egr valve on the truck!


Variable valve timing has eliminated the need for an EGR system.


Remember Leno talking about an Audi brake recall and how few people were getting it done, his line was that they were not able to stop in time at the dealer!

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@Scrapyard-John As well as EGR valves, we used to fight heat riser valves. My 1950 Chevy pickup had a manual choke so it didn’t have or need a heat riser valve. My 1948 Dodge had an electrically operated automatic choke and hence no heat riser valve.

Do not think my truck’s engine has VVT.

Interesting comments about the VVT relationship to EGR valves.

Apparently VVT is used to hold the exhaust valve open a little longer, into the initial stages of the intake stroke. This pulls some exhaust gas from the tailpipe into the combustion chamber. So the EGR function remains, but no need for the EGR valve. As a downside, this EGR-replacement method seems like it could lead to exhaust valve damage. But if it works ok, doesn’t cause valve damage, seems like a great way to eliminate the problematic EGR valve. I wonder if the EGR valve has been eliminated in all recent VVT designs?

Noticed that the 2022 Hyundai Tuscon 2.5 L engine sports both VVT and EGR valve. So it appears not every newer VVT engine design has eliminated the EGR valve.