[Benz430]

This is regarding a 2000 E430.

Problem Story:

Mother told me her E430 loses power at times and she has to release and press the gas 3x until it works again while driving. Her description was difficult to understand, and this issue is not really repeatable. I decided to take the car out with her, and while behind the wheel I pulled out of the neighborhood, and upon reaching 30mph, the car refused to pick up anymore speed. I pushed the throttle further down, however the RPM's were stuck around 3k, and slowly dropping as well as the speed of the car dropping. My mother told me to release the gas and do her 3x method, and I released it and gave it a second, and pushed on the accelerator once and it re-engaged. There were no codes thrown (unsure of any TCM codes), but no OBD codes were thrown.

A few days prior to this however she did have a code in the ECU (P0301, P0305, P0300), however the engine did not display any 'misfiring' and the car did not shake so I cleared those codes.

I read about limp mode regarding the 'power loss' issue she had, however the car wasn't stuck in a gear and progressing in that gear. As I mentioned the RPM's were slowly dropping as well as the speed.

Transmission was serviced at the dealership about 2000 miles ago, and they replaced the shifter bushings as well. Prior to that, we had never experienced this particular issue.

Again I cannot reproduce this issue, and it seems to come about at random. Any input would be greatly appreciated.

 

[Deplore]

Sounds like a clogged catalyst converter.

Bang on all four cats with a rubber mallet. If you hear rattling, clogged cats.

Common theme on W210.

 

[Benz430]

Well we've owned this car for 10 years now, and it always had this 'rattle' noise from underneath the car, (and the car sounding like a diesel). The rattling was never an issue before however and as mentioned prior to the transmission service at the dealership, did not exhibit this odd issue. I seem to consistently see problems with the 722.6 tranny on these forums and people talking about conductor plate replacement as well as possibly solenoid issues. However my mother's car doesn't get stuck in a gear as I've mentioned, but almost as if the pedal doesn't send a 'signal' to the engine randomly and the car acts like it goes into neutral (rpm's slowly dropping and car losing speed) no matter how far you push the pedal. Release it and push it again, and the car engages back.

Again, the issue is intermittent and I cannot reproduce it : /. I'll knock on the cat though which I assume is near the engine on this car.

 

[Check Codes]

You say it didn't throw any codes...but did you actually scan for them when this issue occurred? Many say that simply because there is no CEL.

I would run the adaptive reset noted in the stickies. That will reset the TPS and shift adaptations. If that "fixes it" for awhile, and the symptom recurs, I would replace the TPS, even without a code.

But based on your description, any attention paid to the transmission, without more, is a waste of time.

Good luck.

 

[Deplore]

Well we've owned this car for 10 years now, and it always had this 'rattle' noise from underneath the car, (and the car sounding like a diesel). The rattling was never an issue before however and as mentioned prior to the transmission service at the dealership, did not exhibit this odd issue. I seem to consistently see problems with the 722.6 tranny on these forums and people talking about conductor plate replacement as well as possibly solenoid issues. However my mother's car doesn't get stuck in a gear as I've mentioned, but almost as if the pedal doesn't send a 'signal' to the engine randomly and the car acts like it goes into neutral (rpm's slowly dropping and car losing speed) no matter how far you push the pedal. Release it and push it again, and the car engages back.

Again, the issue is intermittent and I cannot reproduce it : /. I'll knock on the cat though which I assume is near the engine on this car.

You're chasing ghosts that don't exist. If it was truly a transmission issue, once it sets a soft limp home mode, you have to turn off the car to clear the code. Based on your description, the car is drivable immediately after your pedal trick....which means it's not the transmission.

Jack up the car, and hit all four cats along the exhaust tube. You said it's been rattling for years.... That's a definite sign of bad cats. Did I mention that it's a common issue with our car?

 

[Benz430]

You say it didn't throw any codes...but did you actually scan for them when this issue occurred? Many say that simply because there is no CEL.

I would run the adaptive reset noted in the stickies. That will reset the TPS and shift adaptations. If that "fixes it" for awhile, and the symptom recurs, I would replace the TPS, even without a code.

But based on your description, any attention paid to the transmission, without more, is a waste of time.

Good luck.

How would I go about checking for a code while driving? I can give the reset a try though to see if it helps. I have a bluetooth OBD 2 reader and Torque Pro on my phone, can I do a realtime recording and hope it catches the issue while on the road?

You're chasing ghosts that don't exist. If it was truly a transmission issue, once it sets a soft limp home mode, you have to turn off the car to clear the code. Based on your description, the car is drivable immediately after your pedal trick....which means it's not the transmission.

Jack up the car, and hit all four cats along the exhaust tube. You said it's been rattling for years.... That's a definite sign of bad cats. Did I mention that it's a common issue with our car?

I certainly hope it isn't the transmission, this car has been a financial headache for my father and I (already replaced the rear window regulators multiple times, replaced the AC compressor, replaced the radiator, TB, and an assortment of other small items). Thank goodness we can do this type of labor ourselves and save the money of labor costs. I'll run it up on the ramps and smack the cat's with a rubber mallet and check them though. Btw the rattle I mention, I am not sure if it is the cats or heat shields underneath. I was always under the impression that bad cats generally gave off a pungent rotten egg odor, and would also throw an o2 code? We will check them anyway using your method.

I took my mothers car out today for some errands however to see if it would give me that issue, and today though, it ran buttery smooth, aside from sounding like a tractor.....maybe it just hates my mom >_>....

 

[Deplore]

I'll run it up on the ramps and smack the cat's with a rubber mallet and check them though. Btw the rattle I mention, I am not sure if it is the cats or heat shields underneath. I was always under the impression that bad cats generally gave off a pungent rotten egg odor, and would also throw an o2 code? We will check them anyway using your method.

It's possible that the heat shield has gotten loose and is hitting the exhaust, hence the rattling noise.

Easy enough to check while you're underneath the car.

And no, sometimes bad cats just exhibit no symptoms....except that they block/reduce the airflow, creating a significant back pressure that reduces the engine power.

 

[Fluteguy]

When the TPS went out in my '01 E320 it exhibited symptoms like yours. It DID however throw a code that indicated the TPS.

The part is around $100 but the replacement is easy, takes about 5 minutes.

The rattling underneath could be a heat shield or the cats. Check however because I thought that my cats were bad because of a rattle. In my case it turned out to be the charcoal canister purge valve.

So, to reiterate the others statements,

Scan the codes (throwing parts at it is a bad idea)

Have an exhaust shop check the cats

Unless your locked in limp home mode it's probably not the transmission. When that model transmission has issues it's usually electrical. (unless it's just worn out)