Does your Mercedes fail to select a gear, return to N or communicate with the ISM?
The A1644460710 / 1644460710 / A2C53238787 ISM module controls the selection of P, R, N and D in Mercedes-Benz vehicles equipped with DIRECT SELECT and the 722.9 automatic transmission. A faulty module may cause loss of gear selection, a vehicle stuck in P or N, an unexpected return to neutral or no diagnostic communication with control unit A80.
This guide explains where A1644460710 is used, how to identify Siemens VDO and Continental versions, which symptoms and fault codes may indicate an ISM problem, and how VIRGIN preparation differs from cloning. It also describes the correct adaptation sequence using Mercedes Star Diagnosis or Xentry.
You do not need to identify the replacement module on your own. Send us the VIN, a clear photograph of the complete label and the diagnostic fault codes. We can check compatibility and confirm whether VIRGIN preparation or cloning is the appropriate solution.
Need help with an ISM module?
Telephone: +48 888 638 546
Email: sale@ecusale.com
1. Buy a fully tested A1644460710 VIRGIN module
We supply a used module that has passed full testing and has been cleared of the previous vehicle data, ready for adaptation.
VIEW THE A1644460710 VIRGIN MODULE →
2. Send the original ISM for cloning
If VIRGIN preparation is not available for a particular version, we may be able to transfer the data from the original ISM to a compatible replacement module.
3. Browse other Mercedes transmission control modules
Our range also includes other ISM part numbers and Mercedes EGS and TCM transmission control units.
VIEW MERCEDES ISM, EGS AND TCM MODULES →
Contents
- What is a Mercedes ISM module?
- A1644460710 numbers and manufacturers
- Which Mercedes models use A1644460710?
- How to select an ISM by part number or VIN
- Common Mercedes ISM failure symptoms
- Example ISM fault codes
- What to check before replacing the ISM
- What does ISM VIRGIN mean?
- Programming and adaptation sequence
- ISM modules before and after 2013
- Mercedes ISM cloning
- Price and availability
- Other Mercedes ISM part numbers
- Information required for a quotation
- Questions and answers
What is a Mercedes ISM module?
ISM stands for Intelligent Servo Module. It is the actuator used by the Mercedes DIRECT SELECT system and is identified as A80 in Mercedes-Benz diagnostics. The unit is mounted at the transmission and physically carries out the requested selection of P, R, N or D.
| Component | Function |
|---|---|
| Gear selector | Sends the driver's request for P, R, N or D. |
| ISM / A80 | Moves the selector mechanism and monitors the achieved position. |
| Transmission control unit | Controls the transmission and exchanges information with the ISM. |
| Ignition and drive authorisation | Verify authorisation and the selector position required for starting. |
| CAN bus | Provides communication between the vehicle control units. |
The ISM contains electronics, an electric actuator, position sensors and vehicle-specific data. For this reason, a random used module will normally not operate correctly unless it is reset and adapted or cloned from the original unit.
Read more: automatic transmission control modules – TCM, EGS and ISM faults and repair →
A1644460710 – part numbers and Siemens or Continental versions
The module discussed in this article may carry several identifiers on its label.
| Identifier | Meaning |
|---|---|
| A1644460710 | Full Mercedes-Benz part number. |
| 1644460710 | The same Mercedes number written without the initial A. |
| A2C53238787 | Manufacturer number found on the module label. |
| A80 | ISM designation used in Mercedes-Benz diagnostic systems. |
ISM modules may carry Siemens VDO or Continental branding. Earlier parts often have a Siemens or Siemens VDO label, while later production may be marked Continental. Do not select the module only by manufacturer name or housing appearance. The complete Mercedes number, manufacturer number, hardware version, software version and VIN are more important.
Which Mercedes models use A1644460710?
A1644460710 was used mainly in selected Mercedes-Benz vehicles equipped with DIRECT SELECT and the 7G-Tronic 722.9 automatic transmission.
| Model | Series | Example application |
|---|---|---|
| Mercedes M-Class / ML | W164 | Selected petrol and diesel versions with the 722.9 transmission. |
| Mercedes GL | X164 | Selected versions equipped with DIRECT SELECT. |
| Mercedes R-Class | W251 | Selected versions with the 7G-Tronic automatic transmission. |
A1644460710 fits, among others, selected Mercedes ML W164, GL X164 and R-Class W251 vehicles. This list is only a guide. It does not mean that the unit fits every vehicle in the listed series, every engine version or every car fitted with a 722.9 transmission. Mercedes used different ISM versions depending on production date, equipment, transmission configuration and production changes.
If your vehicle is not listed, this does not automatically mean that A1644460710 is unsuitable. Likewise, seeing a model in the table does not confirm compatibility with a particular vehicle. The most important reference is the full part number on the original module label, supported by a VIN check when required.
How to select an ISM module by part number or VIN
Begin with a clear photograph of the complete original label. In addition to the main Mercedes-Benz number, the label may show manufacturer, hardware and production identifiers that are necessary to distinguish visually identical modules.
| Check | What it confirms |
|---|---|
| Mercedes-Benz number | The primary compatibility reference. For this unit it is A1644460710 or 1644460710. |
| Manufacturer number | Helps identify the exact Siemens VDO or Continental version, for example A2C53238787. |
| VIN | Confirms the vehicle model, production date, factory configuration and applicable numbers. |
| Hardware and software version | Affects whether VIRGIN preparation, cloning and correct programming are possible. |
Searching only for “Mercedes W164 ISM” or “722.9 transmission module” identifies a family of parts, not a confirmed replacement. Two modules may look identical but use different electronics, software or data protection. If A1644460710 is not printed on your original unit, send us the label and VIN so that we can check for an approved supersession or identify the correct ISM version.
Mercedes ISM failure – common symptoms
Drivers and workshops most frequently report gear-selection problems or loss of communication with control unit A80.
| Symptom | Vehicle behaviour |
|---|---|
| No D or R | The requested drive or reverse position is not engaged. |
| Transmission returns to N | A gear is selected briefly, then the display or mechanism returns to neutral. |
| Vehicle remains in P | The parking position cannot be released even when the normal starting conditions are met. |
| Gear drops out | The selected position disappears or changes unexpectedly. |
| No communication with A80 | Xentry or Star Diagnosis cannot establish communication with the ISM. |
| Incorrect position display | The displayed selector position does not match the driver's request. |
These symptoms do not prove that the ISM itself is faulty. Low battery voltage, damaged wiring, CAN communication faults, a selector problem, transmission control unit faults or a mechanical transmission issue may produce similar behaviour.
A1644460710 ISM – example fault codes
Fault-code descriptions can differ between Xentry versions and vehicle configurations. A code should therefore be interpreted together with current values, supply-voltage measurements and CAN communication status.
| Example code | Possible diagnostic direction |
|---|---|
| 1904 | Internal mechanism or selector-position problem in component A80. |
| 1918 / 1922 | Possible internal ISM fault, depending on the diagnostic description. |
| 1974 | May relate to the parking position or an implausible ISM position. |
| P179A77 | Selector or actuator position cannot be reached or learned correctly. |
| P179D | Possible ISM actuation, position or communication problem. |
| U-codes / no communication | Check power, ground, wiring, connector condition and CAN before condemning the module. |
A stored or historical code alone is not sufficient grounds for replacing the ISM. Clear the codes with stable battery support and determine which faults return as current.
What should be checked before replacing the ISM?
- Battery and charging voltage: low or unstable voltage can produce communication and position errors.
- Power supplies and grounds: measure them under load rather than relying only on a visual inspection.
- Connector and wiring: look for moisture, corrosion, damaged wires, loose terminals and oil contamination.
- CAN communication: check whether A80 and the related transmission and selector modules are visible in diagnostics.
- Actual values: compare the requested position with the position recognised by the ISM.
- Repair history: establish whether the module has previously been replaced, reset, cloned or adapted.
After a discharged battery, many communication faults may be stored at the same time. Stabilise the supply voltage, clear the fault memory and check which codes return before replacing the controller.
What does ISM VIRGIN mean?
A VIRGIN ISM has been cleared of the previous vehicle data and prepared for assignment to another compatible vehicle. It is ready for programming, but it is not plug-and-play. After installation it requires initial start-up and adaptation.
| Module type | Data condition | Required action |
|---|---|---|
| Standard used ISM | Contains data from the previous vehicle. | Do not install without correct preparation. |
| VIRGIN ISM | Previous vehicle data has been reset. | Perform initial start-up and adaptation with Star Diagnosis or Xentry. |
| Cloned ISM | Contains data transferred from the original unit. | Further work depends on module version and the completeness of the clone. |
VIRGIN preparation is particularly useful when the original module is too damaged for its data to be read. The replacement is then assigned using Mercedes-Benz diagnostic procedures rather than the contents of the failed unit. This requires correct hardware compatibility and a module generation that can be reset.
Cloning is a different process. Instead of clearing the replacement unit, we transfer the original data into it. This method is often required for later versions that cannot be prepared as VIRGIN or when the original configuration must be retained.
BUY A FULLY TESTED A1644460710 PREPARED AS VIRGIN →
How is the A1644460710 ISM programmed?
A VIRGIN module must be commissioned with Mercedes Star Diagnosis or Xentry. A universal fault-code reader will normally not perform the complete personalisation and adaptation procedure.
- Install a compatible ISM and connect a stable battery support unit.
- Run the initial start-up procedure in Xentry or Star Diagnosis.
- Calibrate the selector and the ISM positions.
- Adapt the ISM to the automatic transmission control system.
- Assign the module to the vehicle and complete any required authorisation.
- Clear the fault memory and verify P, R, N and D.
- Check actual values and perform a road test where appropriate.
The sequence matters: calibrate the selector and ISM first, then complete adaptation to the transmission and vehicle. Skipping a stage may leave the vehicle in N or P or cause the faults to return.
Mercedes ISM modules before and after 2013
| Generation | Typical preparation method |
|---|---|
| Many modules produced up to approximately 2013 | May be reset to VIRGIN condition and subsequently adapted. |
| Many modules produced after approximately 2013 | Often require complete online coding or cloning of the original data. |
The year 2013 is only an approximate dividing point. The correct method depends on the exact part number, hardware version and software. Mercedes used different solutions during transitional production periods, and a module may also have been replaced earlier in the vehicle's life. We therefore check the complete label before confirming whether VIRGIN preparation, online coding or cloning is required.
Mercedes ISM cloning
Cloning transfers the data from the original ISM to a compatible replacement. It is used when the module cannot be reset to VIRGIN condition or when the original configuration must be preserved.
You may send:
- the original ISM for assessment and data reading;
- the original unit together with the purchased replacement;
- complete read files, which must first be checked for integrity and completeness.
No communication through the diagnostic socket does not always make cloning impossible. In some cases, the memory can still be read directly on the bench. The result depends on the type and extent of damage.
How much does a VIRGIN ISM module cost?
A fully tested used ISM prepared as VIRGIN usually costs approximately EUR 350–400, depending on the part number and current availability.
| Solution | Approximate cost and requirements |
|---|---|
| Tested used VIRGIN ISM | Usually EUR 350–400; requires adaptation after installation. |
| Cloning into a purchased replacement | May be included in the module price when agreed before purchase. |
| New original module | Often unavailable, subject to a long lead time or priced at approximately EUR 2,000. |
A tested used VIRGIN module is often a faster and more economical solution than a new part. The exact price is confirmed after the complete number has been checked.
Other Mercedes ISM part numbers
A1644460710 is one of many modules in the Mercedes ISM family. Similar appearance does not mean interchangeability, so every replacement must be checked by its complete identifiers.
| Example part number | Important information |
|---|---|
| A1644460610 / 1644460610 | VIRGIN ISM; compatibility must be confirmed by part number and VIN. |
| A0002701752 / 0002701752 | A different ISM version used in selected Mercedes-Benz vehicles. |
| A0002701852 / A2C53423295 | 7G-Tronic ISM; the preparation method depends on the exact version. |
| A0002701952 / 0002701952 | Mercedes 7G-Tronic ISM; do not treat it as the same part as A1644460710. |
| A0002703252 / 0002703252 | A 722.9 version for which cloning may be required. |
| A0044460310 / 0044460310 | Another ISM-family number requiring a separate compatibility check. |
VIEW MERCEDES ISM, EGS AND TCM MODULES →
SEARCH ALL AVAILABLE ISM PART NUMBERS →
What information should be provided for a quotation?
- VIN: helps us verify the exact vehicle version and factory configuration.
- Photograph of the complete ISM label: shows all Mercedes and manufacturer identifiers.
- Model and year: help identify the module generation.
- Complete fault codes: help determine whether the reported problem is likely to involve the ISM.
- Communication status: important when cloning is being considered.
- Required service: VIRGIN preparation, replacement module or cloning.
Contact ECUSale before sending a module. We will confirm feasibility, availability, approximate completion time and the correct shipping procedure.
Telephone: +48 888 638 546
Email: sale@ecusale.com
CONTACT AND COMPANY DETAILS → • SHIPPING COSTS AND DELIVERY TIME → • PAYMENT METHODS →
A1644460710 ISM – questions and answers
| Question | Answer |
|---|---|
| Is an A1644460710 VIRGIN module plug-and-play? | No. It is ready for programming, but after installation it must be commissioned and adapted with Star Diagnosis or Xentry. |
| Will a used ISM from another vehicle work without programming? | Normally not. It must be prepared as VIRGIN or cloned from the original module. |
| How is the A1644460710 ISM programmed? | First calibrate the module and selector, then adapt it to the transmission and vehicle and verify P, R, N and D. |
| Does a return to N always mean the ISM is faulty? | No. Check the battery, power supply, CAN, selector, transmission control unit and transmission mechanics. |
| Does fault code 1974 confirm a defective A80? | It may indicate a parking-position or ISM problem, but power, communication and actual values must also be checked. |
| Can a Siemens ISM be replaced by a Continental unit? | Compatibility must be confirmed from complete part numbers, hardware version and VIN, not only the manufacturer's name. |
| How much does a VIRGIN ISM cost? | A fully tested used module usually costs approximately EUR 350–400, depending on part number and availability. |
Problems with an A1644460710 ISM? Contact ECUSale
No gear selection • transmission returns to N • vehicle stuck in P • no communication with A80 • fault codes 1904, 1974, P179A77 or P179D
Send the VIN, a photograph of the complete label and the diagnostic report. We will check A1644460710 compatibility, VIRGIN availability, cloning options and other suitable Mercedes ISM modules.
Telephone: +48 888 638 546
Email: sale@ecusale.com
