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 Volvo Siemens VDO 30785520AA 5WS40328BT
Vendors's code: 5WS40328BT
Product code: 30785520AA
Barcode:
Code 39:
ISBN:
€243.90
Price
€243.90
€300.00
Price
€300.00
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 Volvo Siemens VDO 30785520AA 5WS40328BT
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Shipping
from
€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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Looking for the 30785520AA ECU for your Volvo?
We offer a used, fully working Siemens VDO engine control unit with part numbers 30785520AA and 5WS40328BT. It fits if the same numbers appear on the label of the ECU in your car. Available locked or unlocked.
Engine control unit Volvo Siemens VDO 30785520AA 5WS40328BT
The Siemens VDO module 30785520AA controls the engine – it reads sensor data and uses it to regulate the fuel system. It is a part for Volvo vehicles. We do not state a model or engine that the label does not confirm; the part numbers decide the fit.
ECU markings
- 30785520AA – Volvo part number
- 5WS40328BT – Siemens VDO number, also printed as 5WS40328B-T
- SID803A – Siemens VDO ECU type
- D1.G – additional marking
Every character must match, including the final letters. If you are not sure, send us a photo of the label.
Symptoms of a faulty engine ECU
- the starter cranks but the engine does not fire,
- the diagnostic tool cannot connect to the ECU,
- an engine warning light and fault codes that remain after replacing sensors,
- signs of moisture or corrosion on the connectors or circuit board.
Before replacing the ECU, check the power supply, earths and wiring loom – a damaged wire or connector can cause similar symptoms.
Locked or unlocked version?
A locked ECU holds the data and immobiliser of the previous car – it is chosen by garages that will program it themselves. The unlocked version is prepared by us before dispatch.
We agree the preparation method case by case – it depends on the software version and the immobiliser. Ask us about it before ordering the 30785520AA ECU.
Read more about the variants on our Locked & Unlocked ECUs page.
Questions and answers
| Can I fit an ECU with a different number suffix? |
|---|
| A different suffix can mean a different software or hardware version. Send us a photo of the label and we will check whether the 30785520AA ECU is suitable. |
| Will the ECU start the engine straight after fitting? |
| The locked version will not – it needs programming and matching to the immobiliser. With the unlocked version it depends on the preparation method, which we agree before purchase. |
| What condition is the ECU in? |
| It is a used part, fully working and in good condition. The warranty period is shown in the product features table. |
Need help choosing? Contact us at contact@auto24parts.com.
