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 MED17.5.5 03C906027Q 0261S04620
Vendors's code: 0261S04620
Product code: B5FD-85633
Barcode:
Code 39:
ISBN:
€284.55
Price
€284.55
€350.00
Price
€350.00
In stock
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 Volkswagen Bosch MED17.5.5 03C906027Q 0261S04620
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€30.00
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shipping
(Poland)
from
€30.00
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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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How do I check whether ECU 03C906027Q will fit?
Read the label on the casing of your unit: the VW number should be 03C906027Q and the Bosch number 0261S04620 (0 261 S04 620 on the label). We are selling a used, working Bosch MED17.5.5.
Engine Control Unit Volkswagen Bosch MED17.5.5 03C906027Q 0261S04620
When a petrol engine suddenly stops starting and the diagnostic tool cannot see the unit, the ECU itself is often to blame. The unit with VW number 03C906027Q belongs to the Bosch MED17.5.5 family, the Motronic for direct-injection engines. It handles fuel metering, ignition and throttle operation. We do not list the Volkswagen model in our data – matching is based solely on the numbers.
How to identify this ECU
- 03C906027Q – Volkswagen number
- 0261S04620 – Bosch number (as printed on the label: 0 261 S04 620)
- MED17.5.5 – Bosch type designation
The single letter Q after the base number defines the software and hardware version. A version with a different suffix may contain different data, so compare the whole number character by character.
Typical failure symptoms
- the engine stalls shortly after starting or will not start at all,
- other control units in the car log a loss of communication with the engine ECU,
- rough running and misfires with no fault in the coils or spark plugs,
- damage caused by water ingress, a voltage surge or failed programming.
Before deciding on a replacement, rule out the fuses, the main power relay and damage to the wiring loom.
How we prepare the unit
If your workshop unlocks and programs ECUs itself, choose the locked version – it contains the data and immobiliser of the car it came from. We prepare the unlocked version in-house before dispatch; this usually takes 1–2 working days.
The availability of a particular method (PIN / CAR PASS, Virgin, IMMO OFF, auto programming, clone) depends on the part number, the software and the car's immobiliser. Get in touch before ordering and we will confirm what is possible. You will find a full description on the Engine control unit (ECU) variants page.
Questions and answers
| Where is the number 03C906027Q? |
|---|
| On the label on the ECU casing, next to Bosch number 0 261 S04 620. |
| Can I fit a unit with a different letter at the end of the number? |
| We do not recommend it without checking first – a different letter means a different software or hardware version. Send us the numbers and we will assess compatibility. |
| What condition is the ECU in? |
| Used, working and in good condition. You will find the warranty period in the product features table. |
If you are unsure about compatibility, write to contact@auto24parts.com – we will advise which option is right for you.
