Recently, my 07' M273 with a 197k miles has developed an unsettling fault. When coming to a stop, the car does not idle down to 600rpm as it used to. Instead, it fluctuates between 800-1,100 rpm and I have to hold the brakes down firm at a stop. Moreover, the car does not want to come to a stop either due to the ghost acceleration requiring much more brake use. Sometimes, when shifting into park the car will rev up to 2,200rpm before idling lower. Cruise control on the highway does not feel smooth, there is hesitation and slight jerks from the rpm variations. The car feels like someone else is stepping ever so slightly on the gas pedal randomly.

Scanned for codes and got this; P2176 / 0217; MP32 (throttle valve actuator) ; The throttle valve is jamming or is stiff. Stored & current.

Cleaned the throttle body, which was dirty. That made no difference whatsoever.

​​​​​​Lastly, a week ago I had the above code along with 1- 1337 – Alternator Serial Interface, 2- 0565 & 0569 O2 sensor; Voltage is too high. Familiar with this being an ECU issue and having replaced my ECU previously, I did just that.

The ECU replacement took care of the CEL, MIL ON, alternator and O2 sensor codes. The throttle valve actuator persisted, prompting me to clean the throttle valve and this is where I am now with the throttle valve actuator code only and no CEL.

How do I fix this issue? GURUS of the great MBWORLD, please bless me with your wisdom.

Thank you!

 

You cleaned the throttle body but how would that help the throttle valve actuator?

Get the actuator replaced.

 

You can also try to do a Throttle Body Idle Relearn/Reset Procedure.
There should be one in Xentry, or your scan tool might have this too.

 

my throttle valve came up a few times in last 500 miles, then the front CAT sensors said they were hot and bothered - swapped the CAT sensors for aftermarket and its all gone normal

 

Thank you Arrie, I think I was overthinking everything.

Will replace and update.

 

Thank you guys, will definitely try the relearn procedure. Let's hope that fixes it.

I haven't had any CAT sensor issues since replacing the ECU.

Do you think it's a good idea to keep driving the car in this state?

 

which state - my car including radar cruise was driving normally with

 

By state, I mean the following symptoms - When coming to a stop, the car does not idle down to 600rpm as it used to. Instead, it fluctuates between 800-1,100 rpm and I have to hold the brakes down firm at a stop.

Moreover, the car does not want to come to a stop either due to the ghost acceleration requiring much more brake use.

Sometimes, when shifting into park the car will rev up to 2,200rpm before idling lower.

Cruise control on the highway does not feel smooth, there is hesitation and slight jerks from the rpm variations.

Another thing I have noticed is that at a stop in drive, while holding the brakes, if I ever so slightly blip the accelerator pedal and release the idle comes down. Weird

Unfortunately, my car was not optioned with radar cruise

 

if you clear all the fault codes - then start and do a short drive which codes come back ?
when did it last get a CPS (crank position sensor) that will lead to strange idle stumbling and stalling - but I'm guessing you'll have lots of issues come up in diagnostics

 

It's a Miracle!

I just did a throttle body relearn procedure and my car was CURED!

I was so relieved and happy, thank you guys for your help !!!

Did about 8 miles so far and all is perfect.

 

I had a thought - I can't remember throttle damper - can be reset - I forget if this is a different setting to throttle body calibration - I think its an electronic control of how the throttle closes, it seemed to help my radar cruise control operate more smoothly at low speeds

 

The throttle body reset or relearn procedure worked great, drove about 50 miles today and no issues. My cruise control works just fine as well

Yeah, the throttle idle calibration was just out of wack, doing the reset ironed it out.