2010 A/T - Hard Converter Lock-Up/Hard 1-2 Shift Mercedes Benz C 300 4MATIC (204.081) V6-3.0L (272.948)
Vehicle: All Technical Service Bulletins
A/T - Hard Converter Lock-Up/Hard 1-2 Shift
Hard 1-2 shift or hard torque converter lockup clutch engagement
Topic number LI27.00-P-049253
Version 1
Design group 27.00 General
Date 04-06-2010
Validity Transmission 722.9
Reason for change Remedy revised / Supersedes DTB S-B-27.00/112
Reason for block
Complaint:
The customer complaint of "Hard shift, presumable the 1-2 shift, occurs when moving off" is often received even though the problem is hard
engagement of the torque converter lockup clutch (KUB) in the start-off process.
In order to permit a clear diagnosis, restrict the transmission to 1st gear by shifting to position 1.
If a jolt occurs at the point where the state of the torque converter lockup clutch changes from "open" to "slipping", then the cause should be sought
in the control of the torque converter lockup clutch.
Cause:
Control of torque converter lockup clutch engagement not optimized.
Remedy:
1. Via DAS menu item "Initial startup", perform transmission software update and then perform SCN coding.
2. Via DAS menu item "KUB adaptation", adapt the torque converter lockup clutch according to the coolant temperature and torque window.
3. Then perform a test drive.
Symptoms
Work units
Validity
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