# What is the color code for CAN Bus?

I would like to know if there is any color code specified for CAN Bus communication wiring, maybe in ISO-11898-1? (I have no free access to the file)

I looked for any official documents without any luck.

When I asked to my colleagues about it, they all agree on the colors (Yellow and Green) but they do not agree if it is:

• Yellow for CAN-H
• Green for CAN-L

• Green for CAN-H
• Yellow for CAN-L

The ISO 11898 standards do not mention practical things such as cables and connectors.

The second-most authoritative source has therefore become the CANopen standards, where DS303-1 specifies things such as standard connectors, pin-outs, cable lengths, baud rates etc. Unfortunately, this document does not mention color-coding either.

Yellow and green seem to be commonly used, though I have seen yellow mean either CAN High or Low. However, just because these colors are commonly used, it does not make them more correct.

I'm guessing that the yellow and green comes from the universally standardized color-coding (same as we use on through-hole resistors). That is: 1=brown, ... 4=yellow, 5=green. For the "mini style" and "micro style" (round M12-like) connectors standardized by DS303-1, CAN High happens to be on pin 4 and CAN Low on pin 5. From DS303-1 7.2:

This enumeration is however not at all consistent with other common, standardized connectors such as d-sub, RJ45 and terminal socket.

CAN does not have a formalized physical-layer specification for conductor colors, or things like connector type or pin-out. There are common practices (like using a 9-pin D-sub connector) but no official standard.

Vehicles these days also tend to have multiple CAN buses, so colors will, of course, vary to keep the different buses straight. I have seen some buses adopt a solid color for CAN-L and a different color striped with the corresponding CAN-L color for CAN-H, to give a visual impression of belonging together.

Overall, as long as you keep track of your conductor colors and pinouts, you can use any color scheme that suits your preference without violating any standards.

I found a link for J1939 cables (not sure if this is generic): see link

Excerpt (see last two lines):

CBL-CAN-01: CAN Cable for DB9 Male Connector
This is a 4-wire color coded cable. One end is DB9 female connector,
it is designed to mate with Au J1939 products at bus side, such as:
J1939 Message Center System, J1939 Data Center System,
J1939 Simulators, etc.

The other side of the cable are 4 pig-tail wires.

Red wire: Power supply, +12V
Black wire: Ground
White (or Yellow) wire: CAN High
Green wire: CAN Low


Red is Power - 12 V
Black is Ground - 0 V
Yellow is CAN High - 2.5 V
Green is CAN Low - 2.5 V

• Thank you Michel, that agrees with my opinion that Yellow for High and Green for Low has more sense. But it is not what I am looking for. I need some techincal documentation to prove it. – ErnstOlch Jan 18 '18 at 12:52
• CAN does not have a formalized mechanical standard for the physical layer - as such, manufacturers will generally use their own standard. I have seen the yellow-green scheme and also a blue and white scheme used in various vehicle buses. So long as you keep track of which colors are which, you can use any colors you like. – Chris M. Jan 18 '18 at 13:26
• @ChrisM Thanks for this ... you should make it an answer, since it seems what ErnstOch is looking for (or at least that it is not a rule.). – Michel Keijzers Jan 18 '18 at 13:59
• Mercedes Benz and MAN buses/trucks have 125kBaud, 250kBaud and 500kBaud buses inside. They run yellow for CAN_H and "blue" for CAN_LOW. It seems that "yellow" is quite common for CAN_HI. – Rohat Kılıç Jan 18 '18 at 14:30
• If someone could cite the actual J1939 document though, that would be a somewhat canonical source. – Lundin Jan 19 '18 at 12:48

In every implementation I've seen, if you can imagine that one color represents "Sky" and the other represents "Earth", those happen to be Hi and Lo, respectively.

• Yellow sun, green grass.
• White clouds, green grass.
• White sky, blue ocean.

Et cetera. These mnemonics seem to fit so well I have to imagine they're intentional.

CAN_H = yellow, CAN_L = green per SAE J1939-11.

This would only apply to J1939-compliant CAN installations.