Published on 10/13/2026
FAKRA is an automotive RF connector system that combines a coaxial interface with mechanically keyed, color-coded housings. Color supports identification; the exact coding and approved part drawing determine mating. A blue, black or water-blue housing is not by itself proof of the vehicle function or electrical rating.
A replacement antenna harness can look correct and still be wrong if its key, cable group or housing variant differs. Automotive routing also adds vibration, temperature, sealing and locking requirements that a generic RF pigtail description does not cover.
This guide explains fakra color codes and reference automotive RF connector standards without assigning a universal vehicle function to each color. SigmaRF can agree a custom assembly from the vehicle/module drawing and exact mating requirements; qualification must be specified separately.
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A reference FAKRA system identifies ISO 20860-1 and SAE/USCAR-18 as interface references. Its product specification is nominal 50 Ω and states a frequency range dependent on cable, connector, assembly and testing. Standards describe defined requirements; citing them does not certify every custom harness.
| Specification layer | What to identify |
|---|---|
| Coaxial interface | Exact plug/receptacle and impedance |
| Housing | Coding letter, mechanical key, color and lock arrangement |
| Cable | Approved cable group, construction and dimensions |
| Vehicle service | Operating band, environment, routing and sealing |
| Qualification | Required evidence, tests and documentation |
Key idea: The correct order is vehicle/module part evidence, approved mating parts, then the harness drawing. Color alone is not a BOM.
The reference coding chart lists 13 keyed codes plus a neutral Z code. The following is a color-identification table, not a universal assignment of radio, GNSS, cellular or camera functions. Vehicle manufacturers can define application usage in their own system.
| Code | Reference color name | Procurement note |
|---|---|---|
| A | Black | Confirm key and exact mating drawing |
| B | White | Confirm key and exact mating drawing |
| C | Blue | Confirm key and exact mating drawing |
| D | Bordeaux violet | Confirm key and exact mating drawing |
| E | Green | Confirm key and exact mating drawing |
| F | Brown | Confirm key and exact mating drawing |
| G | Grey | Confirm key and exact mating drawing |
| H | Violet | Confirm key and exact mating drawing |
| I | Beige | Confirm key and exact mating drawing |
| K | Curry | Confirm key and exact mating drawing |
| L | Carmine red | Confirm key and exact mating drawing |
| M | Pastel orange | Confirm key and exact mating drawing |
| N | Pastel green | Confirm key and exact mating drawing |
| Z | Water blue, neutral coding | Confirm key and exact mating drawing |
There is no J code in this reference sequence. Do not fill gaps alphabetically or infer a part number from a color photo. Manufacturing color differences and lighting can also mislead identification. Use coding letters and the physical drawing for final approval.
Neutral coding needs deliberate review. Do not use a neutral housing as an indiscriminate fix for incompatible vehicle connections. It can defeat the system's mistake-proofing intent if used without the approved design. Confirm the required pair and function with the vehicle or module specification.
Reference FAKRA data show 50 Ω and operation up to 6 GHz with stated dependencies, along with separate working and test voltages. These are reference-system figures, not universal harness guarantees.
| Reference item | Published example | Limit to preserve |
|---|---|---|
| Impedance | 50 Ω | Exact system and cable approval still required |
| Frequency | DC up to 6 GHz in the reference | Cable, connector, assembly and test dependent |
| Return loss | At least 18 dB | Use selected-part band and method |
| Working / test voltage | 60 V DC / 750 V DC | Different service versus test conditions |
| Contact current | Up to 4 A DC in reference, dependent on construction | Not an RF power rating |
⚠️ A FAKRA housing is not blanket waterproofing. Reference guidance requires specific lead-in provisions for waterproof applications. Sealing conditions and the actual variant must be agreed.
Automotive temperature, shock, vibration, locking and mating-cycle requirements need the exact product and qualification plan. Do not borrow a generic family headline for every cable, housing or accessory. A low-power RF sweep is not a complete automotive validation.
Select the connector from the vehicle/module drawing. Name both interface and housing coding, then choose the cable and route. A part with the right color can still have the wrong mechanical key, gender, angle or termination group.
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Approved coded interface
Use the specified coding and matching connector/housing parts so assembly and service remain mistake-resistant.
Unsafe color-based substitution
Do not assign function by generic color folklore or use neutral coding to bypass an unresolved mating requirement.
Distinguish standard FAKRA from other smaller automotive connector systems. Similar application descriptions do not prove direct mating or identical ratings. SigmaRF's connector selection and RF assembly design guides cover the broader interface and routing choices.
Specify the complete RF assembly
Send the frequency band, connector interfaces, finished length and routing drawing. SigmaRF can match the cable and terminations to your application.
Step 01
Recover exact vehicle/module requirements
Provide connector and housing part numbers, coding letter, function and approved mating drawing. Use photos only as supporting identification, not final approval.
Step 02
Define cable and mechanical build
Specify cable group, length, datums, tolerance, body angle, clocking, strain relief and locking/sealing requirements. Follow the actual termination instructions.
Step 03
Separate RF acceptance and automotive validation
Set VSWR/insertion-loss band and test reference planes. Define additional environmental, retention, electrical safety and qualification evidence needed for the program.
SigmaRF VNA-sweeps every assembly for VSWR and insertion loss before shipment. Its overall RF assembly capability spans 100 MHz to 40 GHz across suitable cable and connector systems, not every product discussed here. Volume work is supported in Vadodara, India, with precision work in the Cleveland area, USA. Lead times can be as short as 2 days for suitable builds, subject to parts, quantity and the agreed specification.
SigmaRF's company-wide 40 GHz capability is not a FAKRA harness rating or automotive certification. Confirm the ordered construction and supported qualification route. Its VNA measurement guide covers RF tests; vehicle validation remains an additional requirement.
For an illustrative match calculation, assume measured return loss is 18 dB at one frequency. This is a mathematical example, not a SigmaRF harness result. Return loss is a positive dB measure; reflection coefficient magnitude is less than 1.
Reflection coefficient magnitude = 10^(-18/20) = 0.126
Reflected power fraction = 10^(-18/10) = 0.0158, about 1.58%
VSWR = (1 + 0.126) / (1 - 0.126) = 1.29
Good match does not alone establish insertion loss, shielding, sealing or automotive reliability. Verify each agreed requirement rather than using one RF result as a complete pass. SigmaRF's VSWR guide explains the broader match relationships.
Avoid these FAKRA substitutions
RFQ checks
What is a FAKRA connector?
It is an automotive RF connector system combining a coaxial interface with keyed, color-coded housings. Specify the exact interface, housing coding and approved cable construction.
Do FAKRA colors always mean the same function?
No universal vehicle-function assignment should be assumed from color alone. Use the vehicle/module specification and coding letter for final approval.
What is FAKRA Z?
The reference coding chart identifies Z as water-blue neutral coding. Use it only where the approved design permits; it should not bypass unresolved mating or function requirements.
Is FAKRA 50 ohm?
The reference automotive RF system here is 50 Ω. Confirm the exact parts and approved cable rather than relying on a broad catalog label.
Is every FAKRA connector waterproof?
No. Sealed service needs the exact variant and specified conditions, including cable entry and mated interface. A housing color is not a sealing rating.
Can SigmaRF make a FAKRA assembly?
Provide vehicle/module mating parts, housing coding, cable group, length, route, band and validation requirements. SigmaRF can confirm the build and test scope for the order.
FAKRA color and keying support controlled automotive connections, but the approved drawing decides the product. Color folklore and similar-looking housings are not safe procurement evidence.
Name the exact parts and coding, separate RF acceptance from automotive validation and protect the route. That gives engineers and buyers a repeatable harness specification.
Build an RF assembly around the real requirements
Send the frequency band, connector interfaces, finished length and routing drawing. SigmaRF can match the cable and terminations to your application.