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 Volkswagen Bosch MED17.5.20 03C906022AJ 0261S04137
Vendors's code: 0261S04137
Product code: 642C-968B7
Barcode:
Code 39:
ISBN:
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
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Price 30 euros applies shipments to 5 kg on worldwide. Above this weight, please contact us by email to check price
Shipping cost for the selected product
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Where can you read the number 03C906022AJ on the ECU?
The VW number 03C906022AJ and the Bosch number 0 261 S04 137 are printed on the label on the casing. If both match, this used Bosch MED17.5.20 corresponds to your unit.
Engine Control Unit Volkswagen Bosch MED17.5.20 03C906022AJ 0261S04137
This ECU is the Bosch MED17.5.20 version with the manufacturer number 0261S04137. It has the same base number as the 03C906022A, but a different ending and a different Bosch number, so it is not a replacement for it. In a petrol-engined Volkswagen it is responsible for direct injection and ignition.
Numbers to compare
- 03C906022AJ – VW number
- 0261S04137 – Bosch number, as written on the label: 0 261 S04 137
- MED17.5.20 – Bosch ECU type
The two letters AJ at the end indicate the hardware or software version – compare them carefully with the sticker.
How can you tell the ECU is faulty?
- failure after a voltage surge, a jump start or reversed battery connection,
- no response to the accelerator even though the pedal position sensor is fine,
- incorrect fuel metering in the direct injection system with no injector fault,
- misfires on one cylinder despite a new coil and spark plug.
Start with the power supply and earths, and only then suspect the ECU electronics.
Unlocking and versions on sale
Before dispatch we can prepare the ECU in the unlocked version – this usually takes 1–2 working days. The alternative is the locked version: with the data and immobiliser of the previous car, intended for workshops that will carry out the unlocking, programming and matching in-house.
The unlocking method depends on the specific unit; PIN / CAR PASS, Virgin, IMMO OFF, auto programming or clone are possible depending on the part number, software and immobiliser. Ask before you buy. We have described the variants here: description of ECU variants.
Questions and answers
| Will the 03C906022AJ ECU work without programming? |
|---|
| The locked one needs programming and matching. We prepare the unlocked one before dispatch, and what remains to be done after fitting depends on the chosen method – we discuss this before you order. |
| Which number is more important: 03C906022AJ or 0261S04137? |
| They complement each other. The safest approach is to compare both with the label on your current ECU – if they match, it is the same version. |
| Can I fit an ECU with a different final letter from 03C906022AJ? |
| We do not recommend it without consulting us. The letter denotes the hardware or software version, so a different ending may mean it is not compatible. |
| Is the 03C906022AJ ECU new? |
| No, it is a used unit – in working order and in good condition. You will find the warranty period in the product features table. |
Before buying, you can send the numbers from your ECU to contact@auto24parts.com – we will check compatibility.