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 Polo, Volkswagen Fox 1.4 Siemens 03D906023Q 5WP4084104
Vendors's code: 5WP4084104
Product code: 5WP4084104
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
Engine Control Unit Volkswagen Polo, Volkswagen Fox 1.4 Siemens 03D906023Q 5WP4084104
Administratorem danych osobowych jest Auto24parts. Przetwarzamy je w celu przesłania odpowiedzi na zapytanie. Więcej informacji dotyczących przetwarzania danych osobowych znajduje się w polityce prywatności.
Shipping
from
$30.36
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shipping
(Poland)
from
$30.36
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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
Shipping cost for the selected product
The shipping cost applies to this product (in the selected variant - if applicable). It may change after adding other products to the cart.
Looking for a 03D906023Q ECU for a Polo or Fox 1.4?
We have a used, working Siemens engine control unit with VW number 03D906023Q, used in the Volkswagen Polo and Volkswagen Fox with the 1.4 petrol engine.
Engine Control Unit Volkswagen Polo, Volkswagen Fox 1.4 Siemens 03D906023Q 5WP4084104
The Volkswagen Fox and Volkswagen Polo with the 1.4 petrol engine used this Siemens module. The engine ECU controls fuel injection and ignition, keeps the idle speed stable and monitors the mixture using the lambda sensor. The VW part number is 03D906023Q, and Siemens designates it 5WP4084104. Our data does not give the ECU family, so base compatibility on the numbers.
Numbers to compare
- 03D906023Q – Volkswagen part number
- 5WP4084104 – Siemens number, 5WP40841 04 on the label
5WP numbers are Siemens VDO / Continental designations. The letter Q in the VW number identifies the module version – another 03D906023 ECU may have different software.
ECU failure symptoms
- the engine will not start despite a working starter motor,
- no activation of the coil or injectors,
- the car stalls after a few seconds of running,
- no communication with the module in diagnostics.
First check that power is reaching the ECU and that the connector is clean – only then replace the module.
Locked or unlocked?
In the locked version you receive the ECU with the data and immobiliser of the previous car. This is the solution for workshops that unlock, program and adapt modules themselves. In the unlocked version we prepare it before dispatch, usually within 1–2 working days.
Not every solution (PIN / CAR PASS, Virgin, IMMO OFF, auto programming, cloning) is possible for every number – what counts is the number, software and immobiliser. Please ask before buying. More: ECU preparation options.
Questions and answers
| Does this ECU fit both the Fox and the Polo? |
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| Our data indicates both models with the 1.4 engine. However, compatibility is decided by the number 03D906023Q on your module. |
| What is 5WP40841 04? |
| It is the Siemens number 5WP4084104 as written on the label. |
| What condition is the ECU in? |
| Used, working and in good condition. You will find the warranty period in the product features table. |
Send your ECU's numbers to contact@auto24parts.com – we will check whether this module is the right one.
