Mercedes-Benz 722.9 ISM Intelligent Servo Module Repair and Cloning Service

Mercedes stuck in park? Will not shift? Will not crank? This is the part that failed.

Your car does not need a tow truck and it does not need a dealer. Pull one module off the transmission, ship it to us, and we send back a new unit carrying your own VIN. Bolt it on and drive. You can do the removal in your driveway in about an hour.

Before you order, check your part number against the tables further down this page. Mercedes changed the security architecture partway through this transmission's production run, and that change decides whether this service works on your car. It takes sixty seconds to check and it will save you a wasted shipment.

How this usually starts

It almost never fails all at once. First a message shows up on the dash while you are driving, something like "Drive to workshop without changing gear" or "Service Required Do Not Shift Gears." The car still drives. Most people finish the errand and figure they will deal with it later.

That message is the warning shot. It is the transmission telling you that once you shut it off, it may not be able to select a gear again.

The next morning the stalk does nothing. No click, no response, no gear change. The indicator in the cluster is blank or stuck on P. Turn the key and it may not even crank, because a Mercedes will not engage the starter until something confirms the transmission is actually in park. Nothing is confirming it, because the part that reports position is dead.

The car is now locked in place in your driveway. That is the Intelligent Servo Module, component A80, and this page is about the way out.

Does this sound like your car?

What you are seeing	What is happening
Stuck in park, will not shift into reverse or drive	The ISM cannot move the shift lever inside the transmission, so the car holds Emergency P
Shifter stalk does nothing, no click, no response	There is no cable. The stalk only sends a signal. If the ISM is dead, nothing moves
Will not crank, will not start	The starter stays locked out until the ISM confirms park or neutral. No confirmation, no start
"Drive to workshop without changing gear"	The ISM logged a fault and is warning you it may not shift again once you stop
"Service Required Do Not Shift Gears"	Same failure, different wording depending on model year
Gear indicator blank, or P R N D no longer highlights	The cluster lost the position signal from the ISM
Car dropped itself into neutral while driving	The ISM lost lever position and defaulted out of gear
Was fine last night, locked in park this morning	Classic ISM. Low voltage overnight trips Emergency P and a worn module cannot recover
Cheap code reader shows nothing	Generic scanners cannot see A80. A clean scan on a car locked in park is a clue, not an all clear

This shows up on the E350, E550, C300, C350, ML350, ML550, GL450, GL550, S550, CL550, CLS550, R350, SL550, GLK350 and G550 among others. If it has the 722.9 seven speed and the stalk shifter on the column, it has an ISM and the ISM can fail.

Fault codes that point here: 1994 (A80 cannot reach the specified target position), 1904 (internal mechanism in A80 not in the correct position), 1922 (system shut down due to an internal fault), 1974 (selector lever position implausible due to a fault in A80), 1984, 5399 (ESP CAN signal, gear selected, implausible), C103 ETC (no CAN message received from A80). Xentry will often just say no communication with A80.

First: is your car FBS3 or FBS4?

FBS stands for Fahrberechtigungssystem, the Mercedes drive authorization system. It is what ties your key to the ignition switch, the engine computer and the transmission modules so the car only runs with the right authorization. Mercedes ran FBS3 for years, then moved to FBS4 with much heavier encryption and online authentication through their own servers.

Your ISM is part of that chain, so which system your car uses decides what can be done with the module.

	FBS3	FBS4
Rough model years	2006 through 2014	2014 and 2015 onward, varies by chassis
Can we build it from your VIN alone?	Yes, in most cases	No
Do you need a donor module?	No	Yes, matching part number exactly
Scan tool needed after install?	No	Yes, for lever adaptation
Covered by this listing?	Yes	No. See the red table below

FBS3: these are the part numbers we clone

If the label on your module reads one of these, you are in the right place. Order this service.

Part number	Also stamped as	Typical applications
A0002701652	000 270 16 52, 0002701652	W204 C, W212 E, S212 E estate, W221 S, X164 GL, W164 ML
A0002701752	000 270 17 52, 0002701752	W212 E, W221 S, W251 R, C216 CL, C218 CLS, W164 ML, X164 GL
A0002701852	000 270 18 52, 0002701852	W204 C, W207 E coupe, W212 E, W221 S, C216 CL, C218 CLS, W219 CLS, W209 CLK, W164 ML, W166 ML, X164 GL, X166 GL, W251 R, X204 GLK, W463 G, R230 SL, R171 SLK, R172 SLK
A0002701952	000 270 19 52, 0002701952	7G Tronic applications, confirm by label
A0002703152	000 270 31 52, 0002703152	Later FBS3 722.9 applications
A0002704152	000 270 41 52, 0002704152	Later FBS3 722.9 applications
A0044460310	004 446 03 10, 0044460310	Early 722.9, W164 ML, X164 GL, W221 S, W251 R
A1644460610	164 446 06 10, 1644460610	W164 ML, X164 GL
A1644460710	164 446 07 10, 1644460710	W164 ML, X164 GL, W212 E, W221 S, W251 R, C218 CLS

Supplier numbers on the label. Your module may also carry a Continental or Siemens number instead of, or next to, the Mercedes number. Common ones are A2C53334287, A2C53238787 and A2C53353106. Those are fine. Send us a photo and we will match it.

Reman suffixes. If your number ends in 60 or 80, for example 000 270 18 52 60, that is a Mercedes remanufactured unit of the same part. Same service, same answer.

FBS3 chassis coverage

Model line	Chassis and years
C-Class	W204, 2008 to 2014
E-Class sedan and wagon	W211 late, W212 and S212 through roughly 2013
E-Class coupe and cabriolet	C207 and A207 through roughly mid 2013
CLK	C209 and A209
CLS	W219, and C218 early build
S-Class	W221, 2006 to 2013
CL	C216
ML	W164 all, W166 early build
GL	X164 all, X166 early build
GLK	X204
R-Class	W251 and V251
G-Class	W463 through roughly 2014
SL	R230
SLK	R171, and R172 early build

Gas, diesel, 4MATIC and AMG all use the same module. The engine does not matter here.

FBS4: these we cannot do

Around mid 2013 through 2015, depending on chassis, Mercedes moved to FBS4 and the module is referred to as a DSM rather than an ISM. The data is encrypted and tied to Mercedes servers. We do not offer a service for these units, and we will tell you that up front rather than take your order and mail your module back untouched.

If the label on your module reads any of these, this listing is not for your car:

Part number	Also stamped as	Typical applications
A0002703252	000 270 32 52	W205 C, W212 and S212 E facelift, W222 S
A0002703352	000 270 33 52	W205 C, C207 E coupe, W166 ML and GLE, C292 GLE coupe
A0002703452	000 270 34 52	W447 Vito and V-Class, Sprinter CDI, R172 SLC 250 d and 250 CDI
A0002704252	000 270 42 52	Later 722.9 FBS4 applications
A0002704452	000 270 44 52	W205 C, W212 E, W221 S late, later 722.9 variants
A0002704652	000 270 46 52	Current production unit, supersedes several of the numbers above

FBS4 chassis coverage

These chassis are almost always FBS4 and are outside this service: W205 C-Class, W213 E-Class, W222 S-Class, X253 GLC, W231 SL, C117 CLA, X156 GLA, W447 Vito and V-Class, C292 GLE coupe, later W166 GLE, later X166 GLS, and W212, S212, C207, A207 and C218 built from roughly mid 2013 on.

If your Mercedes is 2015 or newer, assume FBS4 until the label proves otherwise.

How to tell in sixty seconds

1. Read the label on the module. The part number is printed on the plastic housing right next to the electrical connector. Ten digits, usually shown as A 000 270 XX 52. That number is the answer, and it beats every other method on this page. Model year guesses are not good enough.

2. Check your SA codes. If you can pull up your vehicle data card or run your VIN through a Mercedes code decoder, look for SA code 803 or 804. Either one flags an FBS4 car. This is the trick shops use and it works without touching the car.

3. Use the year as a rough filter only. 2006 through 2012 is almost always FBS3 and we can help. 2015 and newer is almost always FBS4 and we cannot. 2013 and 2014 are the crossover years and genuinely go both ways, including within the same model. On those you have to read the label or the SA codes. Do not guess.

4. Still unsure? Ask before you ship. Send us a photo of your module label and we will tell you straight which group you are in, even when the answer means we do not get the sale. We would rather lose an order than take your money and mail your module back untouched.

How it works

1. You remove the ISM. It is bolted to the transmission and reached from underneath. On most models it is a splash shield, one electrical connector, and three bolts. Jack stands and basic hand tools, about an hour. Free step by step removal guides are on youcanic.com. If you would rather not crawl under it, any independent shop can pull it in well under an hour of labor, and they need no Mercedes specific tooling to do it.

2. You ship it to us. Wrap the connector, drop the packing slip in the box, and send it to our office in Baltimore, Maryland.

3. We read your data and clone it onto a new unit. This is the whole trick. Your original ISM holds your VIN, your DAS pairing and your adaptation data. We pull that data off it and write it onto a brand new module. What comes back to you is new hardware that your car believes is the module it has always had.

4. It ships back in 3 to 5 days. Tested before it leaves.

5. You bolt it on and it is over. Three bolts, one connector, splash shield back up. Turn the key and the car shifts. No dealer appointment, no coding software, no scan tool, no VSP paperwork, no tow bill.

Your original module stays with us. You are getting new hardware in exchange, not your old unit patched up.

If your old module is too far gone to read

Occasionally water intrusion or a burned trace takes the memory with it and there is nothing left to clone. You are still not stuck.

We ship you a new unit along with a programming dongle at not extra cost. You install the new ISM on the car first, then plug the dongle into the OBD port. All you need on your end is an Android phone or windows laptop. We connect remotely and program the module to your car ourselves, while it sits in your driveway.

Or if you have  a scanner like the YOUCANIC UCAN-II-D Pro you can perform the programing yourself in 5 minutes or less. You need the phone and a few minutes.

Why the dealer route runs close to $2,000

Your car cannot roll. Stuck in park means the output shaft is locked. It cannot be driven and it cannot be pushed onto a wheel lift. It takes a flatbed with a winch and skates or go-jacks. That is $150 to $350 before anyone has touched the car.

You are not allowed to buy the part. The ISM is a Mercedes Theft Relevant Part. It cannot be sold to you, and it cannot be sold to your independent shop either. Ordering one requires a NASTF registered Vehicle Security Professional to submit a signed D-1 form, your title or registration, government photo ID for both you and the VSP, and a repair order carrying your VIN. That paperwork wall is the real reason people end up at the dealer. It is not the price of the part, it is that the dealer is the only door.

Then it has to be coded. A dealer unit arrives blank. It has to be SCN coded online through Xentry, run through initial startup, and the selector lever has to be adapted. The aluminum mounting bolts are single use and cannot be reused.

What owners actually report paying: $1,000 on a 2014 W212. $1,520 on a 2011 E550 4MATIC. UK owners report over £1,000 for the same job. Add the flatbed and most people land between $1,150 and $2,000 by the time the car is back in their driveway.

Cloning your data onto a new unit skips every one of those steps. Your VIN is already on it before it ships.

Call a tow truck, or do it yourself

	Call a tow truck	Do it yourself
Getting started	Flatbed with a winch and skates, because a car locked in park will not roll onto a wheel lift. $150 to $350 before anyone touches it.	Order this service.
The part	You are not allowed to buy it. Only a dealer can order you one.	Handled. We supply the new ISM unit and put your own data on it.
The work	Dealer labor, plus Xentry SCN coding, plus initial startup and lever adaptation.	One hour on jack stands to pull the old module and bolt the new one on.
Your car	Sits at the dealer for days while you arrange rides.	Never leaves your driveway.
What it costs	$1,150 to $2,000	The price on this page, plus shipping your old module to us.

Why these fail

Worn brushes and a burned commutator in the servo motor, which runs every single time you touch the stalk. Cracked solder joints on the board from years of heat cycling on top of a hot transmission. A shredded drive belt or stripped screw shaft, so the motor spins and the lever never moves, which is fault 1994 in one sentence. Position sensor drift, where the module still moves the lever but can no longer confirm where it landed. Or corroded pins and water intrusion, common on the ML and GL where the module sits right in the splash path.

Every one of those is worn out hardware. That is why the answer is a new unit carrying your data, not a patch on a module that has already given you everything it had.

Questions we get

How do I know if my car is FBS3 or FBS4?
Read the part number on the module label and check it against the two tables above. If you cannot get under the car yet, look for SA code 803 or 804 on your vehicle data card. Either code means FBS4. Model year alone is not reliable in 2013 and 2014.

My car is FBS4. What are my options?
The dealer path, through a NASTF registered Vehicle Security Professional, with the unit SCN coded online through Xentry. We are not able to shortcut that one and we will not pretend otherwise.

My Mercedes will not come out of park. Is it always the ISM?
Not always, but it is the first place to look. Rule out a weak battery and a blown fuse first. If voltage is good and the stalk still does nothing, it is the ISM. Always read the codes with a full system scanner like the YOUCANIC UCAN-II Pro.

My Mercedes will not start and will not crank. Related?
Usually yes, and it is one failure causing both symptoms. The starter stays locked out until the ISM confirms park or neutral.

What does "Drive to workshop without changing gear" actually mean?
The ISM has logged a fault and is telling you that once you stop or shut the car off, it may not be able to select a gear again. Do not ignore it. That message is your window to get the car somewhere convenient before it locks in park.

My part number is not on either list. Now what?
Send us a photo of the label. The lists above cover the numbers we see most, not every number Mercedes ever issued, and supplier numbers like A2C53334287 often appear instead of the Mercedes number.

Do I get my own module back?
No. You get new hardware carrying your data. Your original stays with us.

Will I need the dealer or a scan tool afterward?
No, not on an FBS3 car. The unit ships with your VIN and your adaptation data already on it. Bolt it on and drive. The only exception is if your old module is too damaged to read, and in that case we handle the programming remotely with the dongle and your Android phone.

Is it the ISM or the conductor plate?
The conductor plate causes shifting faults while driving, harsh engagement and gear specific problems. The ISM causes the car to not select a gear at all. If you cannot leave park and the stalk does nothing, that is the ISM.

Can I just buy a new one myself?
Not easily. Mercedes will not sell an ISM to you or to your independent shop through normal parts channels, and a unit bought elsewhere still arrives blank. See the Theft Relevant Part section above.

Can my local shop do the removal?
Yes, and they need no Mercedes specific tooling. It is three bolts and a connector. The specialized work happens on our bench.

Do I send my key?
No. Just the module. Never mail your key. If you want a duplicate key done, that is a separate service and requires that you send us the ignition switch.

How long does it take?
3 to 5 days on our end, plus transit each way.

Start it now

Check your part number against the FBS3 table above, then add to cart and we will email your packing slip. Pull the module this weekend, ship it Monday, and you are driving again instead of paying two thousand dollars and a tow truck.

Not sure it is your problem? Send us a photo of your module label and whatever fault codes you have before you order. We will tell you honestly whether this is it, even if the answer costs us the sale.

Module Medics. Mercedes module cloning and remote programming, Baltimore, Maryland.