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Details
| Specification | Value |
|---|---|
| Brand | ERA |
| MPN | 550777a |
| Number of pins | 2 -pin connector |
OE/OEM numbers (6)
Search by this OE number to find compatible parts
- VW—030 905 377 A
- FORD—3R23-12A699-AB
- CITROËN / CITROËN/PEUGEOT / PEUGEOT—5946 21
- TOYOTA—89615-05010
- CITROËN / CITROËN/PEUGEOT / PEUGEOT—96 168 084
- FORD—BA12-A699A
Where this part fits
Original-fit position for OE 030905377A. The red ring marks where this part installs on the vehicle.
About this product
ERA Knock Sensor (550777A) is manufactured to OEM tolerances, ensuring a direct-fit replacement that restores your vehicle to factory specification without any modification. Technical specifications — Number of pins: Aluminium -pin connector, Alternative Repair Kit: 550777 — are verified against the OEM data sheet to guarantee fitment accuracy and performance parity with the original equipment. Compatible with CITROËN, GEELY, MERCEDES-BENZ, PEUGEOT and 7 other makes vehicles; use the vehicle selector above to confirm exact fitment for your make, model, and engine variant. Fitment data is sourced from TecDoc, the authoritative European parts catalogue. This part supersedes original equipment references: 0 261 231 045, 0 261 231 103, 030 905 377 A, 0907100 and 27 more. Matching these numbers confirms a like-for-like replacement with no loss of function. ERA 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.
Knock Sensor buying guide
Why replace this part?
The knock sensor detects engine detonation, allowing the ECU to retard ignition timing before piston or bearing damage occurs. A faulty knock sensor leaves the engine vulnerable to detonation damage or causes excessive timing retard that reduces power.
Signs you need a replacement
- Check engine light with P0325–P0334 codes
- loss of power and performance under load
- increased fuel consumption
- audible pinging or knocking when accelerating
- poor throttle response
When to replace
No fixed interval — replace on failure. Knock sensors can fail from heat cycles or mechanical vibration over high mileage.
Suitable cars
Equivalent products (27)
Show all 27 OE numbers
Knock Sensor ERA 550777A — compatible car models
| Car models | CITROËN: EVASION MPV (22, U6), XANTIA Break (X1, X2), XANTIA (X1, X2), XM Break (Y4), XM (Y4), XSARA Break (N2), XSARA (N1); GEELY: BL, CK, MR Hatchback, MR Sedan, PU; MERCEDES-BENZ: C-CLASS Coupe (C204), C-CLASS Coupe (CL203), C-CLASS T-Model (S203), C-CLASS T-Model (S204), C-CLASS (W203), C-CLASS (W204), CLC-CLASS (CL203), CLK (C209), CLK Convertible (A209), CLS (C219) (+8 more) |
|---|---|
| Engines | 2.0 16V; 2.0 i 16V; 1.3; C 63 AMG (204.377); C 230 (203.752); C 230 (203.252); C 230 (204.252); C 230 (203.052); C 230 (204.052); CLC 230 (203.752); CLK 280 (209.354); CLK 280 (209.454); CLS 280 (219.354); E 350 CGI (207.457); E 350 CGI (207.357) (+6 more) |
| Year of manufacture | 1989-2018 |
| Manufacturer article number (MPN) | 550777A |
| OE part numbers | 030 905 377 A, 3R23-12A699-AB, 5946 21, 89615-05010, 96 168 084, BA12-A699A |
Compatibility check
Loading vehicle data…
Please wait while we load vehicle compatibility information.Description and what's included
ERA 550777a . Alternative Repair Kit: 550777. Number of pins: 2 -pin connector
- 1x Knock Sensor
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 Knock Sensor compatible with my car?
This Knock Sensor fits CITROËN, GEELY, MERCEDES-BENZ, PEUGEOT, RENAULT and 6 more vehicles. Use the vehicle selector at the top of the page to check exact compatibility — enter your car's make, model, and engine for a confirmed fitment match. All fitment data is verified through TecDoc.
What specifications does this ERA Knock Sensor have?
This ERA Knock Sensor has the following specifications: Number of pins: 2 -pin connector; Alternative Repair Kit: 550777. Check the full specifications table above for complete details.
What OE part numbers does this Knock Sensor replace?
This Knock Sensor replaces OE part numbers: 030 905 377 A, 3R23-12A699-AB, 5946 21, 89615-05010, 96 168 084, BA12-A699A. Cross-reference these numbers with your vehicle's original part number to confirm compatibility.
How much does a Knock Sensor cost?
This ERA Knock Sensor is available for £19.99. Knock Sensor prices vary depending on brand, specifications, and vehicle compatibility. ERA parts offer a balance of quality and value, backed by our 14-day money-back guarantee.
How do I know when to replace my Knock Sensor?
The knock sensor protects the engine from detonation — a fault causes the ECU to retard ignition timing as a precaution, leading to reduced power and fuel economy. The check engine light with knock sensor codes is the primary indicator.
What tools do I need to replace a Knock Sensor?
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 Knock Sensor fitted by a professional mechanic.
Can I use this part as a replacement for OE 030 905 377 A?
Yes, this ERA Knock Sensor is a direct replacement for OE part number 030 905 377 A. 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.
