7-speed 722.9 transmission is widely installed in Mercedes-Benz early 2004 models. 722.9 TCM (transmission control module) has couple advantages such like,
1.Faster & smoother gear shifting to give drivers higher comfort
2.Better fuel economy
3.RPM & Vehicle Speed are better matching
4.Quicker response for downshift/ upshift
So by 2008, it successfully replaced all 722.6 5-speed models usage.
Common symptoms when the transmission model goes wrong:
a. Limp Mode condition appears
b. Transmission stuck in second gear
c. Erratic shifting
d. Can't drive at speed over 40mph
e. Jolting while gears swift
f. Check Engine Light is ON
When you sense these symptoms, don't be panic! You can check transmission fluid oil level first and drive Limp Home Mode car to your auto shop. Very important thing is to let verified repair shops to do automatic transmission unit diagnose via OBD-II port under the dashboard.
Popular fixing way is the replace conductor plate A 0034460310 (see our 32729-83140 conductor plate), control module sensor or valve body according to error code reading results (here to see what error codes mean). New TCU will require SCN & CVN coding which can only be performed by the dealer or an authorized repair shop.
We all know how complicated transmission system is and to be honest not many mechanics experience fixing such problems. Specific process like swift the gear in, pouring transmission fluid into chamber, then pairing the new control plate to the computer. Any step moves wrongly, not only original problem can't be solve but new error may occur!
HJL transmission team successfully helps repair shops globally to shoot TCU problem via on-line remote diagnosing process and plate coding. Such dedicated process required verified mechanics skill and patience, so we strongly recommend car owners to let your trustful auto shop to proceed whole processes themselves or let your auto shop to contact us before your purchase.
Welcome Repair Shop Owner contact us for cooperation discussion!
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