w211 downshifting randomly
Thread Starter
Junior Member
Joined: Jul 2021
Posts: 30
Likes: 0
E240, SL500, GL500 4matic, ML350 4matic
w211 downshifting randomly
Hello all,
I've got a 2003 E500.
Few days ago, the car started to downshift randomly when I'm cruising at normal speeds.
Example: I was driving the car at 100 km/h on the highway. As you know, this speed only requires a slight punch on the gas. the car downshifted to a lower gear and got stuck in it until I've applied full throttle or reach 4000 rpm.
Note that this is definitely not the "limp mode" because it can get out of the gear.
Also, I got the gear chip changed few months ago and got it inspected again after this problem and it is in mint condition.
Any help? this is really annoying
I've got a 2003 E500.
Few days ago, the car started to downshift randomly when I'm cruising at normal speeds.
Example: I was driving the car at 100 km/h on the highway. As you know, this speed only requires a slight punch on the gas. the car downshifted to a lower gear and got stuck in it until I've applied full throttle or reach 4000 rpm.
Note that this is definitely not the "limp mode" because it can get out of the gear.
Also, I got the gear chip changed few months ago and got it inspected again after this problem and it is in mint condition.
Any help? this is really annoying
Out Of Control!!
Joined: Apr 2019
Posts: 11,919
Likes: 6,768
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
2003 V8...
no codes... then next step is to clean the sludge out of conductor plate and shaft sensors.
Check data when this happen to confirm inconsistent reading of shaft sensors.
Check data when this happen to confirm inconsistent reading of shaft sensors.
Thread Starter
Junior Member
Joined: Jul 2021
Posts: 30
Likes: 0
E240, SL500, GL500 4matic, ML350 4matic
That’s what my mechanic suggested. I’m pretty sure that my accelerator pedal sensor is also running bad. Few months ago it was sluggish and even if I floor it the car won’t respond, when I restart it it goes fine, again this case was few months ago. however, it doesn’t pop any fault codes. Is there any chance that it is the cause?
what would you recommend to start with?
Out Of Control!!
Joined: Apr 2019
Posts: 11,919
Likes: 6,768
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
gradually failing...
thanks man.
That’s what my mechanic suggested.
I’m pretty sure that my accelerator pedal sensor is also running bad.
Few months ago it was sluggish and even if I floor it the car won’t respond, when I restart it it goes fine, again this case was few months ago. however, it doesn’t pop any fault codes. Is there any chance that it is the cause?
what would you recommend to start with?
That’s what my mechanic suggested.
I’m pretty sure that my accelerator pedal sensor is also running bad.
Few months ago it was sluggish and even if I floor it the car won’t respond, when I restart it it goes fine, again this case was few months ago. however, it doesn’t pop any fault codes. Is there any chance that it is the cause?
what would you recommend to start with?
"it was sluggish and even if I floor it the car won’t respond" is exactly a limp-mode and without any CEL the pedal is guaranteed 100% mint.
The pedal sensor is the most scrutinized sensor of the ECU inputs. It's a dual reversed circuit. It sets code in a heart bit just like it's counterpart: the throttle body. Bosch purposely does not make these parts fail. The sensing is done contactlessly with zero rubbing potentiometer whatsoever.
Back onto your failing tranny, you could try a reset to force it to "relearn shift points" but at that stage this step may get you into a Uber back seat.
Right now it is giving you early warnings to address a specific problem. You can tackle this yourself or pay $5k to get this standard job done.
Thread Starter
Junior Member
Joined: Jul 2021
Posts: 30
Likes: 0
E240, SL500, GL500 4matic, ML350 4matic
Understand that what you describe as:
"it was sluggish and even if I floor it the car won’t respond" is exactly a limp-mode and without any CEL the pedal is guaranteed 100% mint.
The pedal sensor is the most scrutinized sensor of the ECU inputs. It's a dual reversed circuit. It sets code in a heart bit just like it's counterpart: the throttle body. Bosch purposely does not make these parts fail. The sensing is done contactlessly with zero rubbing potentiometer whatsoever.
Back onto your failing tranny, you could try a reset to force it to "relearn shift points" but at that stage this step may get you into a Uber back seat.
Right now it is giving you early warnings to address a specific problem. You can tackle this yourself or pay $5k to get this standard job done.
"it was sluggish and even if I floor it the car won’t respond" is exactly a limp-mode and without any CEL the pedal is guaranteed 100% mint.
The pedal sensor is the most scrutinized sensor of the ECU inputs. It's a dual reversed circuit. It sets code in a heart bit just like it's counterpart: the throttle body. Bosch purposely does not make these parts fail. The sensing is done contactlessly with zero rubbing potentiometer whatsoever.
Back onto your failing tranny, you could try a reset to force it to "relearn shift points" but at that stage this step may get you into a Uber back seat.
Right now it is giving you early warnings to address a specific problem. You can tackle this yourself or pay $5k to get this standard job done.
anyway, I tried resetting it but it didn’t work out.
Furthermore, when the transmission gets stuck at a specific gear, I just move the gear knob to right and it upshifts directly. I didn’t know this would work but it actually did.
back to the problem, as I understand from what you’re saying, I should ignore the accelerator sensor right now and focus on the transmission mechanical components (conductor plate).
am I right?
Last edited by Amjad007; Jul 22, 2022 at 02:14 PM.
Trending Topics
Out Of Control!!
Joined: Apr 2019
Posts: 11,919
Likes: 6,768
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
To be honest, spare parts out here aren’t that expensive. A clean transmission imported from japan with labor charges costs 700$.
anyway, I tried resetting it but it didn’t work out.
Furthermore, when the transmission gets stuck at a specific gear, I just move the gear knob to right and it upshifts directly. I didn’t know this would work but it actually did.
back to the problem, as I understand from what you’re saying, I should ignore the accelerator sensor right now and focus on the transmission mechanical components (conductor plate).
am I right?
anyway, I tried resetting it but it didn’t work out.
Furthermore, when the transmission gets stuck at a specific gear, I just move the gear knob to right and it upshifts directly. I didn’t know this would work but it actually did.
back to the problem, as I understand from what you’re saying, I should ignore the accelerator sensor right now and focus on the transmission mechanical components (conductor plate).
am I right?
That is your fix, don't mess with anything else.
Get one on!
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Junior Member
Joined: Jul 2021
Posts: 30
Likes: 0
E240, SL500, GL500 4matic, ML350 4matic
Those spare parts are imported from UAE. Even if the transmission costs around 700$, I got tired of throwing money on the car without knowing the exact cause of the problems. I am also afraid of changing the whole transmission and having the problem still exist.
That's why I am really into knowing the exact cause first and then moving on to fixing it in the best way.
My mechanic suggested changing the accelerator sensor and then changing all transmission seals + cleaning the valve body.
He is assuming that the accelerator sensor is bad also because the throttle response reading in STAR is mistaken or sometimes with no response at all.
That's why I am really into knowing the exact cause first and then moving on to fixing it in the best way.
My mechanic suggested changing the accelerator sensor and then changing all transmission seals + cleaning the valve body.
He is assuming that the accelerator sensor is bad also because the throttle response reading in STAR is mistaken or sometimes with no response at all.
Out Of Control!!
Joined: Apr 2019
Posts: 11,919
Likes: 6,768
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Those spare parts are imported from UAE. Even if the transmission costs around 700$, I got tired of throwing money on the car without knowing the exact cause of the problems. I am also afraid of changing the whole transmission and having the problem still exist.
That's why I am really into knowing the exact cause first and then moving on to fixing it in the best way.
My mechanic suggested changing the accelerator sensor and then changing all transmission seals + cleaning the valve body.
He is assuming that the accelerator sensor is bad also because the throttle response reading in STAR is mistaken or sometimes with no response at all.
That's why I am really into knowing the exact cause first and then moving on to fixing it in the best way.
My mechanic suggested changing the accelerator sensor and then changing all transmission seals + cleaning the valve body.
He is assuming that the accelerator sensor is bad also because the throttle response reading in STAR is mistaken or sometimes with no response at all.
Thread Starter
Junior Member
Joined: Jul 2021
Posts: 30
Likes: 0
E240, SL500, GL500 4matic, ML350 4matic
I'm really surprised.. I left the car sitting for a few days and now after a 2-hour rolling, the problem doesn't seem to exist!
I already ordered the accelerator pedal sensor and I'm waiting for its arrival in the next 3-5 days.
I don't know if this might relate but the weather is a bit cooler here today ( 33 c ). When normal days it's around 45 c
I already ordered the accelerator pedal sensor and I'm waiting for its arrival in the next 3-5 days.
I don't know if this might relate but the weather is a bit cooler here today ( 33 c ). When normal days it's around 45 c
