Chamz333

I recently had my W212 E350 realigned, after we got the car back from the repair center the mechanic mentioned that the TPMS needs to be replaced, but when I checked the tire pressure on the dash monitor gauge it has been tampered with to 60psi .. so I changed it back to the correct tire pressure and obviously didn’t have my TPMS replaced .. now I know this shop cannot be trusted..

anyways do you think that the mechanic can tamper with the ECU programmed it and lowered the “Idle” , because my car now shakes on idle on stops and when turning the steering wheel ..

S-Prihadi

Dont call it ECU CODING. Idle speed is adjustable.

So what is your hot engine idle RPM now ?
There is a parameter to adjust idle using Xentry or proper aftermarket scanner.


If you are on electric or hydraulic power steering, making a turn takes extra power and if the engine is not in good form, it may reduce RPM even further by much.
Check if any evap or vacuum hose got loosen, sounds like your have intake leak or vacuum leak as they call it and the unmetered extra air at idle causing bad combustion, during higher RPM it will not effect badly, only at idle RPM.

Chamz333

I did a diy smoke test and found a pinhole leak upfront by the flappers 2 hoses had a leak and got that sealed and did another smoke test cannot see any other leak, I also replaced most of the parts that worn out , cleaned out the throttle body, replaced MAF, sparks, transmission mount etc.. it is running a little better I’d say maybe 50% of vibration is gone, passed SMOG no codes .. RPM is around 500-650 vibration is still there, did the engine mount test seems good, engine is not trying break off to run away.. so I was thinking if my ECU or IDLE has been tampered with and in the field to purchase / looking for a good reader coder that can take on Merc and other cars like Lincoln / ford, Lexus etc .. as my family grows

Chevota

There is a Neutral/Park idle speed and a Drive/Reverse idle speed. I assume that's what you meant 500-650. 650 N/P seems reasonable but 500 D/R seems low to me. I would assume more like 550 to 600, but maybe someone with a 350 can chime in.
If the TPMS said it was set to 60, then I'd assume that didn't happen by accident. And if below 60, which I also assume your pressure is, then it was alerting you to low pressure when you picked up the car? If so, and it only did it after they touched it, then they made that change to scam you.
I'd imagine very few people know how to check that and it's probably an easy scam.
For vibration I'd assume motor mounts. You need to lean on it pretty good to see the eng jump up and show bad mounts, and imo do it in 1st gear, not the default 2nd gear. Then do the same in Reverse to check the other side.
HP Tuners is pretty cool to see and chart data. $pendy at I think $400, but it can record all your stuff from before you even start the car to shutdown. Excellent for catching little or intermittent things. Something to consider...

Chamz333

yes they changed the reading .. we make it a habit to set the pressure at what is recommended and was changed while at repair center .. and yes they tried to SCAM


Edit: No there was no alert that I know off , my daughter drove the car home, but I was advised the the TPMS needs to be replaced and I declined the repair because the tires where due to be replaced and Costco can replace the sensor if needed, and if it makes any difference this E350 4matic has Sport (S) mode.