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Details
| Specification | Value |
|---|---|
| Brand | MOBILETRON |
| MPN | vr-b855 |
| Voltage [V] | 12 V |
| Manufacturer Restriction | Bosch |
| Plug Type ID | CPU |
| Operating voltage [V] | 14 V |
| Version | Test Adaptor COM02 |
| Version | B-Circuit |
| Version | Test Adaptor COM01 |
| Specification | Self Mode |
| Specification | LIN 1.3 |
| Specification | Variable V Setting |
| Specification | Temperature Current |
| Specification | Standby Mode |
| Specification | LIN (COM) |
| Specification | LIN-1-1 |
| Specification | 19200 (4 Byte) |
| Specification | Default Mode |
| Specification | Field Current |
| Specification | Field Out Duty Montr |
| Specification | Leakage Current Cntr |
| Voltage from [V] | 14.1 V |
| Voltage to [V] | 14.5 V |
| Charging Voltage [V] | 14.3 V |
OE/OEM numbers (2)
Search by this OE number to find compatible parts
- AUDI—03G 903 803B
- VW—03L 903 803B
Where this part fits
Original-fit position for OE 03L903803B. The red ring marks where this part installs on the vehicle.
About this product
When alternator regulator performance matters, the MOBILETRON VR-B855 delivers — built to the same dimensional and material standards as the original part it replaces. The part is built to the following specification: Voltage [V]: Zinc V, Manufacturer Restriction: Bosch, Plug Type ID: CPU, Operating voltage [V]: Nylon V, Version: Test Adaptor COM02. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. This part supersedes original equipment references: 0-125-811-028, 0-125-811-033, 0-125-811-035, 0-125-811-073 and 9 more. Matching these numbers confirms a like-for-like replacement with no loss of function. MOBILETRON is a recognised supplier of automotive replacement components to independent workshops and dealer networks across Europe. All parts are sourced from authorised distribution channels and carry full manufacturer traceability — you receive exactly the same component supplied to professional garages and dealer workshops. If fitment or specifications do not match your vehicle, our technical team can help identify the correct alternative — use the vehicle selector or contact us with your VIN for a guaranteed-fit recommendation. Replacing worn components on schedule preserves your vehicle's safety, reliability, and resale value — and aftermarket parts from established brands deliver OEM-equivalent performance at a fraction of the dealer price. Every part is dispatched from our UK warehouse with a 30-day money-back guarantee and free hassle-free returns.
Suitable cars
Vehicle matches are curated from manufacturer data
Confirmed fits based on manufacturer data.Equivalent products (11)
Alternator Regulator MOBILETRON VR-B855 — compatible car models
| Manufacturer article number (MPN) | VR-B855 |
|---|---|
| OE part numbers | 03G 903 803B, 03L 903 803B |
Compatibility check
Loading vehicle data…
Please wait while we load vehicle compatibility information.Description and what's included
MOBILETRON vr-b855 . Charging Voltage [V]: 14,3 V. COM ID Code: 40. Manufacturer Restriction: Bosch. Operating voltage [V]: 14 V. Plug Type ID: CPU. Specification: 19200 (4 Byte). Specification: Default Mode. Specification: Field Current
- 1x Alternator Regulator
Shipping, returns, warranty
Free UK delivery on orders over £99.00. Express and standard shipping available.
- Standard delivery: 2-5 business days
- Express delivery: 1-2 business days
- Free returns within 14 days
- All parts backed by manufacturer warranty
Warranty: 12-month manufacturer warranty on all parts. 14-day money-back guarantee if the part doesn't fit your vehicle.
Frequently Asked Questions
Is this Alternator Regulator compatible with my car?
Use the vehicle selector at the top of the page to check compatibility. Enter your car's make, model, and engine — we'll confirm whether this Alternator Regulator fits. All fitment data is verified through TecDoc.
What specifications does this MOBILETRON Alternator Regulator have?
This MOBILETRON Alternator Regulator has the following specifications: Voltage [V]: 12 V; Manufacturer Restriction: Bosch; Plug Type ID: CPU; Operating voltage [V]: 14 V; Version: Test Adaptor COM02; Version: B-Circuit. Check the full specifications table above for complete details.
What OE part numbers does this Alternator Regulator replace?
This Alternator Regulator replaces OE part numbers: 03G 903 803B, 03L 903 803B. Cross-reference these numbers with your vehicle's original part number to confirm compatibility.
How much does a Alternator Regulator cost?
This MOBILETRON Alternator Regulator is available for £25.99. Alternator Regulator prices vary depending on brand, specifications, and vehicle compatibility. MOBILETRON parts offer a balance of quality and value, backed by our 14-day money-back guarantee.
How do I know when to replace my Alternator Regulator?
Regular inspection of your Alternator Regulator is recommended as part of routine vehicle maintenance. Watch for changes in performance, unusual noises, or visual signs of wear. Consult your vehicle's owner manual for manufacturer-recommended replacement intervals specific to your make and model.
What tools do I need to replace a Alternator Regulator?
Tools required vary by vehicle make and model. Generally, a basic socket set, screwdrivers, and vehicle-specific tools may be needed. We recommend consulting a workshop manual for your specific vehicle, or having the Alternator Regulator fitted by a professional mechanic.
Can I use this part as a replacement for OE 03G 903 803B?
Yes, this MOBILETRON Alternator Regulator is a direct replacement for OE part number 03G 903 803B. It is manufactured to meet or exceed original equipment specifications, ensuring proper fitment and performance. All cross-reference data is verified through TecDoc.
Related categories
Common OE numbers for this part
Common original equipment numbers linked to stocked alternatives.
