OBDII & C55
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Junior Member
Joined: Apr 2007
Posts: 15
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2005 C55
OBDII & C55
I would like to know if it is worth it and doable to try to use an OBDII device to smooth out my torque converter lock-up symptoms. My goals are:
1) Minimally, resetting the ECU with it so I don't have to sit in the car for 2 minutes, just plug in a OBD device and press a button. 2) After an ECU reset, I can only drive the car a couple of days before the harsh shifting around 1600 rpm returns.
So resetting the ECU seems to do the trick but just want a quicker way. The instructions I follow are turn key to pos 2, press gas peddle to floor for 4 secs, turn key to pos 1, WAIT 2 MINUTES. Obviously eradicating the jerk is another option but from what I read - no one has a solution for that. One final question is getting a OBD device good for anything else and if so any recommendations on a unit that works with a 2005 c55 ?
1) Minimally, resetting the ECU with it so I don't have to sit in the car for 2 minutes, just plug in a OBD device and press a button. 2) After an ECU reset, I can only drive the car a couple of days before the harsh shifting around 1600 rpm returns.
So resetting the ECU seems to do the trick but just want a quicker way. The instructions I follow are turn key to pos 2, press gas peddle to floor for 4 secs, turn key to pos 1, WAIT 2 MINUTES. Obviously eradicating the jerk is another option but from what I read - no one has a solution for that. One final question is getting a OBD device good for anything else and if so any recommendations on a unit that works with a 2005 c55 ?
Senior Member
Joined: May 2010
Posts: 380
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From: Seattle, Warshington
2005 C55, 2006 Ram 2500 MegaCab diesel, sold 2001 Dodge 2500 Cummins, sold 87 190e-16v, sold 97 e420
Define your harsh symptoms. A lot of people blame the torque convertor when it more an issue of the amount of air the computer is sensing running through the motor. You may have a dirty MAF, fouled plugs, or dirty throttle body. If the motor senses more throttle input but reduced air, it is going to act funny and shift funny. I had that problem. It went away after I did all three items.
Thread Starter
Junior Member
Joined: Apr 2007
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2005 C55
With trans in S, if I keep it in 1st and take off normally right around 1500 rpm give or take a 100 there is a very noticable jerk. Repeat that but take of more aggressively, same rpm but the jerk is less pronounced. If I reset the ECU the jerk almost disappears but I notice it is occurring much higher in the rpm band like over 2000. After driving around for perhaps 10 to 50 miles, the jerk returns. It is very annoying when trapped in traffic because you are constantly going from dead stop to maybe 10mph and each time it traverses 1500 rpm there is a jerk. To be honest, it is so annoying that this could end up being the one reason sell it or trade it in.
I read somewhere about the throttle body and some vacumn tube getting clogged but haven't been feeling well enough to check it out, hopefully this week. The car as 58k so I don't think it is time for plugs. There is an awful "crud" going around in elementary schools here in So Cal and my wife is a teacher and it seems like as soon as I get clear of "crud" I end up with "son of crud". I hope there is no "daugher of crud" or "crud 2" -- at least long enough for me to check that out.
I read somewhere about the throttle body and some vacumn tube getting clogged but haven't been feeling well enough to check it out, hopefully this week. The car as 58k so I don't think it is time for plugs. There is an awful "crud" going around in elementary schools here in So Cal and my wife is a teacher and it seems like as soon as I get clear of "crud" I end up with "son of crud". I hope there is no "daugher of crud" or "crud 2" -- at least long enough for me to check that out.
Last edited by Effe; Apr 1, 2012 at 06:43 PM.
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Joined: May 2006
Posts: 4,539
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From: Southern Cal
a C32 AMG & S-Works Tarmac
I always thought the tranny jerk was more of a problem on the C32 than the C55.
I don't know what the answer is. I've tried many things, including getting the torque converter replaced under warranty. Nothing has helped in the long run.
I do the reset to smooth it out also. When combined with leaving the A/C compressor off, it makes for a smoother drive.
By the way, to the best of my knowledge, the 2 minute wait is a myth. I have not intentionally waited the 2 minutes in years. Sometimes, I have restarted the car within seconds of the reset. If you don't want to believe me and still prefer to wait the 2 mins, just do the reset when you get home, then exit the car. Done. It should be more than 2 minutes before you go back to the car, most of the time. (that is what I try to do most often).
I don't know what the answer is. I've tried many things, including getting the torque converter replaced under warranty. Nothing has helped in the long run.
I do the reset to smooth it out also. When combined with leaving the A/C compressor off, it makes for a smoother drive.
By the way, to the best of my knowledge, the 2 minute wait is a myth. I have not intentionally waited the 2 minutes in years. Sometimes, I have restarted the car within seconds of the reset. If you don't want to believe me and still prefer to wait the 2 mins, just do the reset when you get home, then exit the car. Done. It should be more than 2 minutes before you go back to the car, most of the time. (that is what I try to do most often).
Senior Member
Joined: May 2010
Posts: 380
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From: Seattle, Warshington
2005 C55, 2006 Ram 2500 MegaCab diesel, sold 2001 Dodge 2500 Cummins, sold 87 190e-16v, sold 97 e420
You guys missed the point about my post. It is not the tranny's fault with the jerk. The car has adaptive learning so it try to work around a problem.
Once you do all that, I guarantee you, when the car is warm in in S, she'll run up to 2000 rpm at light throttle and downshift like it was new without throttle.
- Change the type of gas you are running. My car does not do that with Chevron gas.
- Clean your MAF
- Clean your throttle body.
Once you do all that, I guarantee you, when the car is warm in in S, she'll run up to 2000 rpm at light throttle and downshift like it was new without throttle.
