Mercedes Scan Tool Valve Body reprogramming issue - Received by email

Donny Manager Colorado Posted   Latest  
2005 Mercedes-Benz SL500 5.0L 7-spd (722.9) — WDBSK75F55F095019

Scan Tool would not complete coding

See extended digest below.

VIN: WDBSK75F55F095019

Model Type: 230 SL

Model Year: 2005

Engine Type: 273 8-cyl V-8

Trans Type: 722.9 - Automatic Electronic 7-Speed

Mileage: 175000

Area - Transmission/ETC

Malfunction - Transmission does not shift

Condition - always


Recap: installed MB valve body. Performed initial startup. No transmission codes. Spent weeks chasing CAN issues. Rechecked the programming and performed SCN coding again. We were convinced the valve body was defective. Brought the vehicle to my dealer. They called me back the same day telling me the vehicle was all set; $355.44 please. They confirmed the multitude of CAN issues. They checked the coding of the transmission control unit and found that the new valve body was not activated. They performed initial startup, performed the teach ins and activated the control unit. Fixed. What happened? Xentry sure didn’t offer any hint as to the problem.


Back at this project. I have another car in the shop with the pan off and i borrowed the valvebody. Plugged it in this car and my can issues are gone and live data shows gear position changes when I move shaft on this valvebody. Have you seen valvebody /ETC module bad out of the box?


2005 sl 500 new valvebody installed. test drive car and it is in limp mode. no transmission codes . we have event codes stored in esp module for can communication trans​.​sporadically disturbed and fault in can communication with cgw. esp has had a used unit installed with same results. installed and reprogramed a used cgw and same results. trans has no codes or events. in live data it shows under gear change transmission actual gear neutral and target gear neutral with no change with shifter. in shift programs selector range valve position value is initializing. shows emergency running as no. trans has adaption for y3/8s1. goes through that adaption fine as it has me shift through each gear and sds beeps and confirms as complete. just removed pan to make sure i had not made any errors installing the valvebody. all looks good. starting to believe this new valvebody control unit is bad. i also checked shifter module live data and it shows correct movements of the shifter. this car also had a battery draw that was found to be the audio gateway module. i have had the doors latched closed for testing. went to put this car out a few days ago mand noticed that the display is red and say put in park with key in my hand.


We had a W220 with a 722.9 transmission on the lift opposite this car. We decided to check the CAN C voltages at the transmission on this car which had no problems with voltages on our car. There probably is documentation for this information but I could not find it. With the key on both cars had similar readings: 2.3 volts on one wire and 2.6 on the other. With the key off the test car, CAN C wires both went to zero volts. On our problem car the voltages only went down to .9 volts each. The CAN connectors were unplugged one at a time from the X30/18 CAN connector junction block until the voltages at the transmission went to zero. Note: if CAN B is awake the CAN C voltage drops to zero as CAN B goes to sleep. The offending plug goes to the gateway. With this CAN plug disconnected Xentry was used to run a quick test: there was no communication with the ESP with “!” present on the test results; the ETC was totally missing. With the key on 2.3 and 2.6 volts were still present at the ESP CAN plug as well as the transmission CAN plug. Is the next step to replace the gateway? 


For the car not to kill the battery, the CAN needs to go to sleep. At the CAN connectors, one by one (not color coded), each CAN connector was unplugged until the CAN went to sleep. The vehicle was then scanned to determine which module was now missing; the Comand was missing. The CAN goes to sleep with the Comand (radio display/most master) disconnected.

Is the Comand defective or is a module on the Most keeping it awake? Each Most module was disconnected one by one until the Comand did go to sleep. The offending module is the tuner; it needs to be replaced. With the Comand attached and the tuner removed the CAN B goes to sleep and the Comand stays asleep. With CAN B asleep, the key off draw is now 90 mamp. This is on the very high side of acceptable. The transmission still does not shift.


Examined the CAN connectors at the left front door sill. There was no water damage, and everything looked perfect.

The alarm/siren is defective, so we unplugged it. There is a 4 amp draw most of the time. The car has been attached to a power supply for as long as we have had the car. 

Out of the blue the command flashes, then the cluster & clock come alive. Next, the car tries to connect a call & the SOS becomes active. After that, the command lights up with the Mercedes Star as the background. This sequence may be repeated or may stop.


The 15R circuit is repaired as good as it is going to be until a new EZS is available. We cut the large pink/yellow wire inbetween the EZS and fuse box. We installed a 4 pin relay to power up 15R at the fuse box. With no load the 15R pink/yellow wire maintained battery voltage: we used this to control the relay we just installed. We ran a fused wire from the starter battery to power the relay. As far as the car is concerned circuit 15R works as designed.

The SRS is happy and the fault list is smaller. But, my CAN issue is still there and the transmission does not shift.


Marty said we should not overlook AB code 9002: Control module N2/7 (restraint systems control unit)(circuit 15R): No voltage

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Alan Anacki

Bridgewater Motor Works, Ltd.

Dave Owner/Technician

We will assume you are using an official MB Xentry tester with valid software subscription. The part number for your valve body should be … We had an E63 a few weeks ago we could not code valve body and it turned out dealer had ordered incorrect part #. Always have them verify part number on a valve body order. I've spoken with another shop who has had trouble coding a conductor…

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Marvin Owner/Technician

I just don't see how Xentry didn't complete the whole process. Unless, the tech performing the programming does not do it correctly. I have done so many of these VB's and conductor plates. It's always the same process: PROGRAM, SCN CODE, REMOVE TRANSPORT PROTECTION, PERSONALISATION, ACTIVATION AND RANGE SENSOR RELEARN. No more no less. If you don't do complete initial start up, of course you…

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