TCU limp while driving?
06-20-2018, 09:57 AM
#1
Super Member
Thread Starter
TCU limp while driving?
I noticed this today while cruising on the highway to work.
Temps were normal, no CEL.
Downshifts suddenly became uncrisp and slow, almost like in comfort mode (I was in M). There was no bang above 2k rpm doing 5 > 4, like I always get. It was slow and quiet. Upshifts were slower but less noticeable.
This only happened a few times in the past and usually happened after I put the car into neutral to rev. After I put it back into D sometimes the transmission would become slow on M until I restart the car.
No neutral revving this time, just normal highway driving. So I’m a bit worried. Anyone else experienced this?
Temps were normal, no CEL.
Downshifts suddenly became uncrisp and slow, almost like in comfort mode (I was in M). There was no bang above 2k rpm doing 5 > 4, like I always get. It was slow and quiet. Upshifts were slower but less noticeable.
This only happened a few times in the past and usually happened after I put the car into neutral to rev. After I put it back into D sometimes the transmission would become slow on M until I restart the car.
No neutral revving this time, just normal highway driving. So I’m a bit worried. Anyone else experienced this?
06-20-2018, 03:34 PM
#2
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'13 C63 AMG P31
This happens from normal driving. Get on it a couple of times and it will liven it right back up. Mine does the same if I am just cruising around (in M) and not really planting my foot down.
06-20-2018, 03:46 PM
#3
Super Member
Thread Starter
so you’re saying In addition to restarting which resets it, hammering it (assume in one of the auto modes) also does the trick?
06-21-2018, 08:14 AM
#4
MBWorld Fanatic!
I swear....I thought I had lunched the motor somehow (valves - but thankfully not)
The neutral revving, is to do with some kind of torque mis-calculation. I get it sometimes if I hit the limiter at 8k. I'm not sure if it's so much of a tranny issue than it is an ECU calibration issue....
06-21-2018, 10:56 AM
#5
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'13 C63 AMG P31
I'm not sure if restarting the car resets it (never stopped to notice or try), but hammering it in any mode should do the trick. I'm in M mode 99.95% of the time, so I notice it a bit more when I'm not sprinting or driving hard. As soon as I get on the gas once or twice, the car livens up more.
06-21-2018, 12:49 PM
#6
Same goes for comfort mode. If your cruising for a bit, its very "efficient". If you step on it once for a decent accel, the car will keep its rpms up and downshift a bit sooner. Seems like the car adapts constantly to driving style.
