A faulty transmission control module (TCM) most often causes limp mode with the gearbox stuck in one gear, harsh jolts when you select D or R, erratic gear changes, flashing PRND letters and a gearbox or engine warning light. However, the same symptoms are often caused by a low gearbox oil level, a weak battery, a poor earth or a faulty sensor. To test a transmission control module, start by checking the battery and reading the fault codes with a diagnostic tool that can talk to the gearbox control unit, then check the power supply, the connector, the oil and the live data. Below we explain the symptoms, the diagnostic steps and what the most common fault codes mean.
Engine control unit Mercedes A6421502179 0281012012
Vendors's code: 0281012012
Product code: E0E0-14154
Barcode:
Code 39:
ISBN:
£431.66
Price
£431.66
£530.94
Price
£530.94
Select a product option:
Individual variants may differ in price
product option
Important: Depending on the ECU type and vehicle model, not all of the options listed below may be available.
To select the correct option for your vehicle and ECU, please contact us before purchasing:
contact@auto24parts.com
1. Locked
This option is intended for professional workshops with the required specialist equipment and technical knowledge.
The ECU has been removed from a vehicle intended for recycling and still contains the immobilizer data and other information from the previous vehicle. Before it can be used in another car, it must be unlocked and then programmed using specialist automotive diagnostic equipment.
2. Unlocked
Several preparation methods may be available. The possible options depend on the ECU type, vehicle model and immobilizer system. Please contact us before purchasing, as some preparation methods are not available for every ECU.
Our electronics specialists can prepare the ECU in one of the following ways:
a) ECU with PIN code (Car Pass)
The PIN code is supplied, but programming with a suitable diagnostic tool is still required. After installing the ECU, it must be reset using the supplied PIN code and then programmed to the vehicle’s immobilizer system.
b) VIRGIN ECU
The data from the previous vehicle is removed and the ECU is restored to a clean, factory-like state. After installation, it must be programmed to the vehicle using a compatible specialist diagnostic tool. Unless another preparation method is specified in the product description, this is the standard unlocking option for most of our ECUs.
c) Plug & Play – IMMO OFF
The immobilizer function is disabled in the ECU. After installation, the engine can start without additional immobilizer programming. Please note that the vehicle will no longer have an active immobilizer function, and an immobilizer warning light or fault code may remain, depending on the vehicle model.
d) Plug & Play – Automatic Programming
After installation, the ECU automatically learns and saves the required vehicle data. No additional programming is normally required.
e) Plug & Play – 1:1 Clone
The data from your original ECU is copied to another fully functional ECU. The cloned unit is then ready for installation without additional programming.
You must send us your original ECU so that we can transfer its data to the replacement unit.
The original ECU must have working communication with the vehicle, a diagnostic tool or our programming equipment. If the required data cannot be read, a complete 1:1 clone may not be possible.
3. Complete Plug & Play Set
A complete matched set containing the ECU, immobilizer components and all other parts required to start the vehicle without additional programming. All components supplied in the set must be installed in the vehicle.
Important:
Dispatch time depends on the selected option. If an unlocked or specially prepared version is ordered, the preparation service usually requires an additional 1–2 business days.
Ask about the product
Engine control unit Mercedes A6421502179 0281012012
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£22.75
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(Poland)
from
£22.75
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shipping
(Poland)
Price 30 euros applies shipments to 5 kg on worldwide. Above this weight, please contact us by email to check price
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Where to find number A6421502179 on Mercedes engine control units?
Engine control unit A6421502179, used and inspected. Compare the numbers with the original in your car.
Is engine control unit A6421502179 the right part for your Mercedes?
Engine control unit A6421502179 is a used electronic module that manages engine operation. It is intended for Mercedes, and it is matched by the numbers in the listing, not by the car make alone. The listing does not state the car model or year, so we do not give them in the description and match the part by its numbers. The listing also gives the markings CR4.11. They help tell the control unit versions apart, but the full part number is what decides compatibility.
Numbers to compare
You will find the numbers on the label of the control unit, while catalogues list them as a single string:
- A6421502179, car manufacturer's original number,
- 0281012012, control unit manufacturer's number.
Check the numbers on your control unit and compare them with those above. If any of them differs, contact us before ordering.
Control unit variant
This listing is for a control unit in the following variant(s): Locked / Unlocked. We describe the differences between the variants (locked, unlocked, Virgin, IMMO OFF, Plug and Play, clone, full set) on the ECU preparation options page. Before buying, send us the numbers from the label and we will confirm which variant is available for that number.
Faults that call for checking the control unit
- the engine will not start although the starter motor works and there is fuel,
- the diagnostic tester cannot connect to the control unit,
- the car loses power or goes into limp mode,
- faults appear and disappear, usually once the engine has warmed up.
Before replacing the control unit, check the condition of the connector and the power supply wires. After fitting, the fault codes usually need to be cleared and, if necessary, the control unit programmed for the car.
Questions and answers
| Does a lit engine warning light always mean a faulty control unit? |
|---|
| No. Read the fault codes first, because the cause may be a sensor, the wiring or the power supply. |
| What do the markings CR4.11 in the listing mean? |
| They are markings of the version or type of the control unit. They help tell the units apart, but the full part number is what decides compatibility. |
| Can I send a photo for a compatibility check? |
| Yes. Contact us and send a photo of the label on the original control unit, and we will help you check whether this part will fit. |
| Is this a new part? |
| No. We sell used original control units, each one inspected before sale. You will find the warranty period in the product features table. |
Want to be certain? Send us the numbers from the housing of your control unit, and together we will check whether this part will fit.
