MBenzOwner

Has anyone seen an auxiliary transmission pump failure without any xentry codes? What would be the presentation outside of maybe sluggish gear changes after restarting from an eco stop. Would it affect the ability of the car to restart from an eco stop?

fabbrisd1

From your other Fresh Posts - what yr/model/current miles ?

Transmission is generally Transmission Maintenance depending on Yr/Miles.

Disconnect Start/Stop reading this Thread in Cousin Site (or search forum here):

https://www.benzworld.org/threads/pe...#post-17629048

MBenzOwner

2015 c300 w205 100k

transmission overall is fine no issue. Fluid change at 70k. Was just wondering if anyone has had a auxiliary pump failure since that is connected to the start stop system but I would only expect it to maybe cause slow shifting right after a restart not prevent a restart.

I’m hesitant to disconnect the battery sensor not knowing what the full repercussions would be over time. I would still like to figure out the root cause if possible hence trying to look at it from different angles.

I figured at least these discussion would help others.

fabbrisd1

The "root cause" of exactly what issue - how long have you owned your 100K mile C300 ? YES - you have slow shifts after EVERY startup.. whether you are Starting your MB in the garage and pulling out.. or re-starting at a stop sign.

If it bugs you - without disconnect on the "wire job" - either (1) you manually Turn-Off start/stop feature - or you go to eBay and get a OBD programmed module that will reprogram Eco/Start-Stop - often called Last Mode -m if you turn your MB off with ECO Off - then next restart ECO stays in all profiles off until your turn it back on - if you turn off your MB with ECO on - next restart ECO stays on... etc. Once re-programmed - you won't have your "issue"

MBenzOwner

The root cause of why the car has intermittent trouble restarting from an ECO stop which basically leaves you stalled at a red light. Looked at all the common electrical causes.

It basically stalls 1 out of 5 times on restart, no crank but can be restarted by placing into n or P. I’ve owned the car for 6 yrs.

Disconnecting the battery sensory may affect other systems. The modules are a good patch but I wanted to make sure this issue is not a harbinger of something worse that will leave me unable to start at all one day.

In your judgement it seems to be that low ATF fluid pressure won’t prevent a restart in the eco start stop process just lead to sluggish shifting until the main pump can take over. I only
ask because some posts mention dealers changing it when people had similar issues though with much lower mileage and early on in their purchases.

I posted elsewhere but here is the link of what happens.

E55Greasemonkey

People actually like eco stop? I think it's awfully annoying. The miniscule fuel savings will be outweighed by more frequent battery replacements, thus no monetary benefit.

MBenzOwner

Not a real benefit unless you have prolonged stops in traffic like in an urban area like NYC during rush hour or pass through a lot of red lights. I think in slow, rolling traffic it isn't that helpful since the engine can't turn off.
I think it is mostly for regulators to improve city MPG on paper. Plus once you add complexity to a system, there are more failure points. This is especially problematic for the long-term holders of the vehicles.
Though I can't prove it, you could argue some of the early green benefits are washed out by the additional parts and upkeep needed later for the system.