722.9 transmission slipping - error codes P0894, P0732
Thread Starter
Newbie
Joined: Nov 2019
Posts: 4
Likes: 3
From: Yerevan, Armenia
Mercedes-Benz C300 4MATIC Sport 2014
722.9 transmission slipping - error codes P0894, P0732
Hi Friends,
I just got C300 4MATIC Sport 2014 delivery from the US in a quite good condition. 70K miles and the car looking very fresh, both exterior and interior.
When test driving, I noticed a problem. Only under hard acceleration(from standing to pressing the accelerator all the way down) it jerks when switching to second gear. Like 2 gear is slipping and controller blocks the acceleration - I guess to prevent burning the shift packets in transmission. It is like the gas pedal is losing response and is off.
If you then re-apply the acceleration it catches up quickly and accelerates very fast, shifts like butter for the other gears as far as I can tell.
Local MB dealer just diagnosed and printed two error codes confirming what I already saw and there is no more detailed info from the service center. Folks advised to check the oil level and change it to see if it will fix it (costs around $350). If the problem is still there, I kind of just throw away that $350, since if you open it up again you throw away the oil.
Other mechanics I consulted(transmission experts) want to rip the transmission open to change the "slipping packet" without any electronic diagnostics. No one talks about oil levels/condition, solenoids, electronics, control unit, speed sensors, torque converter, etc - just rip it open right away
MB Service center I assume can just swap parts, like entire transmission or torque converter or the control unit... which will cost a few thousands $.
What are my options here? Has anyone had a similar problem with 722.9 transmission?
I assume the correct and cost-effective order of things to check will be:
If I drive normally, without hard acceleration from standing position, the problem is not noticeable. I'm not driving the car now not to damage the transmission.
Error codes below:
P0894 - Transmission is slipping
P0732 - Gear 2 is implausible or transmission is slipping
Many thanks for any and all advice.
I just got C300 4MATIC Sport 2014 delivery from the US in a quite good condition. 70K miles and the car looking very fresh, both exterior and interior.
When test driving, I noticed a problem. Only under hard acceleration(from standing to pressing the accelerator all the way down) it jerks when switching to second gear. Like 2 gear is slipping and controller blocks the acceleration - I guess to prevent burning the shift packets in transmission. It is like the gas pedal is losing response and is off.
If you then re-apply the acceleration it catches up quickly and accelerates very fast, shifts like butter for the other gears as far as I can tell.
Local MB dealer just diagnosed and printed two error codes confirming what I already saw and there is no more detailed info from the service center. Folks advised to check the oil level and change it to see if it will fix it (costs around $350). If the problem is still there, I kind of just throw away that $350, since if you open it up again you throw away the oil.
Other mechanics I consulted(transmission experts) want to rip the transmission open to change the "slipping packet" without any electronic diagnostics. No one talks about oil levels/condition, solenoids, electronics, control unit, speed sensors, torque converter, etc - just rip it open right away
MB Service center I assume can just swap parts, like entire transmission or torque converter or the control unit... which will cost a few thousands $.
What are my options here? Has anyone had a similar problem with 722.9 transmission?
I assume the correct and cost-effective order of things to check will be:
- Oil level check/adjustment - transmission needs to be warm at 45C when measuring level.
- Then try to get more detailed transmission diagnostics - I assume Service center shall be able to pull out more info than ODB2 readers from Amazon right?
- Try to replace solenoid responsible for 2nd gear...
If I drive normally, without hard acceleration from standing position, the problem is not noticeable. I'm not driving the car now not to damage the transmission.
Error codes below:
P0894 - Transmission is slipping
P0732 - Gear 2 is implausible or transmission is slipping
Many thanks for any and all advice.
Out Of Control!!
Joined: Sep 2018
Posts: 14,694
Likes: 4,584
From: unbegrenzt
2017 GLE350 4MATIC
Start with easy and less expensive, progressing to more difficult and more expense options.
Try to establish if the transmission is actually slipping. If it is slipping, it happens for a reason. You must find the reason.
- read codes and truly understand what they are telling you
- change fluid and filter
- confirm sensors function
- consider conductor plate replacement https://www.autoecu.com/transmission...iABEgLq_fD_BwE
- consider torque converter + lockup clutch assembly replacement
- consider transmission replacement
- consider vehicle replacement
Try to establish if the transmission is actually slipping. If it is slipping, it happens for a reason. You must find the reason.
- read codes and truly understand what they are telling you
- change fluid and filter
- confirm sensors function
- consider conductor plate replacement https://www.autoecu.com/transmission...iABEgLq_fD_BwE
- consider torque converter + lockup clutch assembly replacement
- consider transmission replacement
- consider vehicle replacement
MBWorld Fanatic!
Joined: Aug 2013
Posts: 1,364
Likes: 149
2012 C300 4MATIC Sport
First, check out this thread and see if it's the same problem reported here over and over: https://mbworld.org/forums/c-class-w...g-problem.html
The solution turned out to be a software update to the Transmission Control Unit (and the ECU). I had this jerk problem and it cost me $100 at the dealer to update the software and reset adaptations and the car was back to being butter smooth in all gears shifts. My problem was the downshift from 3 to 2 and 2 to 1.
The solution turned out to be a software update to the Transmission Control Unit (and the ECU). I had this jerk problem and it cost me $100 at the dealer to update the software and reset adaptations and the car was back to being butter smooth in all gears shifts. My problem was the downshift from 3 to 2 and 2 to 1.
Thread Starter
Newbie
Joined: Nov 2019
Posts: 4
Likes: 3
From: Yerevan, Armenia
Mercedes-Benz C300 4MATIC Sport 2014
First, check out this thread and see if it's the same problem reported here over and over: https://mbworld.org/forums/c-class-w...g-problem.html
The solution turned out to be a software update to the Transmission Control Unit (and the ECU). I had this jerk problem and it cost me $100 at the dealer to update the software and reset adaptations and the car was back to being butter smooth in all gears shifts. My problem was the downshift from 3 to 2 and 2 to 1.
The solution turned out to be a software update to the Transmission Control Unit (and the ECU). I had this jerk problem and it cost me $100 at the dealer to update the software and reset adaptations and the car was back to being butter smooth in all gears shifts. My problem was the downshift from 3 to 2 and 2 to 1.
Last edited by hovgrig; Dec 2, 2019 at 11:05 AM.
Thread Starter
Newbie
Joined: Nov 2019
Posts: 4
Likes: 3
From: Yerevan, Armenia
Mercedes-Benz C300 4MATIC Sport 2014
Thread Starter
Newbie
Joined: Nov 2019
Posts: 4
Likes: 3
From: Yerevan, Armenia
Mercedes-Benz C300 4MATIC Sport 2014
I have a good news guys, you were right. Although many mechanics diagnosed transmission wrongly and wanted to "fix" transmission by dissembling it, I finally managed to find a mechanic and simply some missing blue fluid which completely solved the problem.
What is strange, transmission was missing 2.5L of oil! And no any leaks detected, everything was clean under the car. I wonder who and how serviced the car and missing to add so much fluid.
Also wonder why Mercedes doesn't put a level sensor, should be easy enough thing to do. I was not driving the car, but had to do one or two high RPM tests for mechanics to reproduce the problem before adding fluid. Hope it didn't cause physical damage to transmission with so much missing fluid.
Anyways, problem solved! Thank you friends! If someone will see similar symptoms, and also see bad shifting on uphill, even on low RPM, first thing to check is the oil level for sure!
What is strange, transmission was missing 2.5L of oil! And no any leaks detected, everything was clean under the car. I wonder who and how serviced the car and missing to add so much fluid.
Also wonder why Mercedes doesn't put a level sensor, should be easy enough thing to do. I was not driving the car, but had to do one or two high RPM tests for mechanics to reproduce the problem before adding fluid. Hope it didn't cause physical damage to transmission with so much missing fluid.
Anyways, problem solved! Thank you friends! If someone will see similar symptoms, and also see bad shifting on uphill, even on low RPM, first thing to check is the oil level for sure!
Trending Topics
Newbie
Joined: Jul 2023
Posts: 3
Likes: 0
2009 mercedes c63
I have a good news guys, you were right. Although many mechanics diagnosed transmission wrongly and wanted to "fix" transmission by dissembling it, I finally managed to find a mechanic and simply some missing blue fluid which completely solved the problem.
What is strange, transmission was missing 2.5L of oil! And no any leaks detected, everything was clean under the car. I wonder who and how serviced the car and missing to add so much fluid.
Also wonder why Mercedes doesn't put a level sensor, should be easy enough thing to do. I was not driving the car, but had to do one or two high RPM tests for mechanics to reproduce the problem before adding fluid. Hope it didn't cause physical damage to transmission with so much missing fluid.
Anyways, problem solved! Thank you friends! If someone will see similar symptoms, and also see bad shifting on uphill, even on low RPM, first thing to check is the oil level for sure!
What is strange, transmission was missing 2.5L of oil! And no any leaks detected, everything was clean under the car. I wonder who and how serviced the car and missing to add so much fluid.
Also wonder why Mercedes doesn't put a level sensor, should be easy enough thing to do. I was not driving the car, but had to do one or two high RPM tests for mechanics to reproduce the problem before adding fluid. Hope it didn't cause physical damage to transmission with so much missing fluid.
Anyways, problem solved! Thank you friends! If someone will see similar symptoms, and also see bad shifting on uphill, even on low RPM, first thing to check is the oil level for sure!
MB World Stories
The Best of Mercedes & AMG
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
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
Out Of Control!!
Joined: Sep 2018
Posts: 14,694
Likes: 4,584
From: unbegrenzt
2017 GLE350 4MATIC
How many miles on your transmission now?
You could try to reset adaptations in XENTRY. Only XENTRY can do this. No other OBD tool can do it, and no urban legend "reset procedure" will do this. Either buy a XENTRY setup or have an indy shop do it.
If a fluid change and XENTRY work doesn't help, the next replaceable item is the conductor plate, including speed sensors that fail with time and solenoid valves that plug over time.
If the conductor plate doesn't solve it, likely clutch packs are needed which amounts to a rebuilt transmission.
You could try to reset adaptations in XENTRY. Only XENTRY can do this. No other OBD tool can do it, and no urban legend "reset procedure" will do this. Either buy a XENTRY setup or have an indy shop do it.
If a fluid change and XENTRY work doesn't help, the next replaceable item is the conductor plate, including speed sensors that fail with time and solenoid valves that plug over time.
If the conductor plate doesn't solve it, likely clutch packs are needed which amounts to a rebuilt transmission.
