Canbus wiring question

[JanD]

The SCCM (steering wheel buttons module(limit/cruise/up/down...)(KK3T-3F944-AB) has a can bus(yellow/green-blue/gray). One of 4 canbusses. I presume HS-CAN2? This goes across other modules like the obd gateway. But I'm looking for a more accessible connector. In some info it would be under the seat (passenger seat module) or behind the rear view mirror (camera module) but both are not present. I only found a keyless entry module there(other color wires). Are there members who have more access to that kind of information? A diagram/manual would be nice but not necessary. Just some help with other possible access points would be great so I don't need to disassemble the whole car.
So, in short: where does that canbus go across? What is also connected to that specific one (1/4)?

I presume that for search purposes there will be needed more accurate vehicle data? But if no one is able to help, that kind of info seems to soon.

Thanks!

[Airthies]

Can't really help unless we know what vehicle model year etc as there are so many differences.

Secondly what is your aim?
There may be different options to achieve the same thing.

I can't claim to know a major amount about the canbus systems but sometimes easier to narrow things down


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[JanD]

There are some vehicle properties under my posts. Some other info:

Factory type: FCC
Variant: BKFB1ABX
Version: R3WRASAACA2SAA
Cathegory: N1
95,60kW

My goal is gain easy access to that peticular canbus in a reachable place. Like under the seat or under the glove compartment so I can snif that canbus when I find the time. Probably a year long project since I don't have that much available time(filling the gaps). I don't want to disassemble each time. Just plug in and go forward.

The eventual goal is to deal with belgian rediculous road regulation. It's 30/50/70 and very rapdly changing (read: slowing down). We have a real hunt for money by penalties. You can google it. It's everywhere in the news. I use the limiter constantly but it eat focus and distracts playing constant piano on the buttons. So if i have 3 shortcut buttons (30/50/70) it would be much safer and less stressfull. I could just drive the speedlimit (I hear you say) but it is that insane here that nobody is able to. Even the slow old folks are getting penalties now. One town gathered millions in a few weeks for installing zone 30 cameras. You can't find anyone who hasn't got a ticket yet. So, the limiter really helps but is not without risk.

Also, i'm stuborn and cheap so i want to make it myself . Or is such thing easily available?

[metalworker0]

Don't really know what you're asking

but put it to google in the form of this question

"where can the can bus be intersected without using the diagnostics port"

The answer

AI Overview
To read CAN bus data without using the diagnostic socket (OBD-II), you can intercept the wiring at several key locations where Electronic Control Units (ECUs) communicate directly. The best approach is to locate a twisted pair of wires—typically orange/green and orange/brown for high-speed CAN, or blue/red and blue/white in heavy vehicles—within the main harness.
Here are the primary locations to tap into the CAN bus:
1. Behind the Instrument Cluster
The dashboard instrument cluster is often the easiest, most accessible spot that carries significant vehicle data (engine speed, odometer, doors).
Method: Remove the dashboard panel and locate the connector on the back of the instrument cluster. Look for a tightly twisted pair of wires.
2. Vehicle Modules (ECU, ABS, BCM)
You can directly tap into the wiring harness connecting to major, accessible modules.
ABS System: Look for a pair of twisted wires leading to the ABS control module, but take care to ignore the four individual wheel speed sensor wires.
Front Electronic Module (FEM) / Body Control Module (BCM): Frequently located behind the glovebox or in the passenger-side kick panel (e.g., BMW F87).
Engine Control Unit (ECM/PCM): While often in the engine bay, these are prime hubs for CAN communication.
3. Behind the Radio/Infotainment System
In many vehicles, the infotainment system (radio, navigation unit) is connected to the CAN network to display car settings.
Method: Remove the radio unit and look for the harness connector carrying twisted pair wires.
4. Steering Column or Tachograph
Steering Column: In some vehicles, specifically light-duty trucks like the Iveco Daily, a 4-cable connector (green, white, pink, white) exists where green/white is the CAN pair.
Tachograph: Connector A behind the tachograph (often found in trucks/commercial vehicles).
Important Precautions for Tapping
Identify the Correct Pair: CAN bus uses a twisted pair (CAN High and CAN Low) to reduce noise. Using non-twisted, untwisted, or incorrect wires can cause communication errors (the car may act "possessed").
Avoid Damaging Wires: Back-probing a connector is preferred over piercing the insulation. If you must pierce, use proper T-tap connectors.
Soldering: Junctions should be soldered or securely spliced, not merely twisted together, to avoid data loss.
Avoid Excessive Length: Do not allow the untwisted length of the wire to be more than 1–2 cm.
Note: For many newer vehicles, the OBD port is behind a gateway, so direct tapping is required for full, unfiltered access to all networks.


my next question was
"can you control canbus functions anywhere without the diagnostic port"

answer

AI Overview
Yes, it is possible to control CAN bus functions outside of the OBD-II diagnostic port. The CAN bus is a network that spans the entire vehicle, and any two-wire twisted pair connection labeled CAN High and CAN Low (part of the same bus) can be used to read or inject messages. However, doing so requires bypassing the vehicle's security gateway (which restricts OBD-II traffic) and direct access to the wiring harness.
Methods to Control CAN Bus Without the Diagnostic Port
Direct Wire Tapping: You can locate and tap into CAN wires behind the instrument cluster, radio, infotainment system, or at various control modules (e.g., Door Module, Body Control Module).
Accessing Vehicle Gateways/Modules: Modern cars often have multiple CAN buses (e.g., powertrain, body, infotainment). You can connect to specific, less-secured, or higher-speed buses directly at the module responsible for the function you want to control.
Inductive Probes (Read-Only): For non-invasive, read-only monitoring, special inductive probes can read CAN traffic by clamping over the insulation of the wires without piercing them.
Key Considerations
Safety Criticality: Many systems, such as braking (ABS) and steering, are safety-critical. Unauthorized manipulation can be dangerous and is usually restricted by the car's gateway.
Wire Identification: You must accurately identify the CAN High and CAN Low wires for the specific bus, often requiring a multimeter or oscilloscope.
Voltage Levels: Tapping into the bus requires connecting to the 12-volt system and, in some cases, bypassing gateway modules that limit communication from the diagnostic port.
Voiding Warranty: Modifying or piercing wiring harnesses to tap into the CAN bus will likely void the vehicle warranty.
Controlling a vehicle's CAN bus outside of the OBD-II port can have significant safety and legal implications. The CAN bus is a complex network, and improper interaction can lead to unpredictable vehicle behavior or damage to critical systems. Accessing the CAN bus without the diagnostic port typically involves interacting directly with the vehicle's internal wiring or control modules. Modern vehicles often have security gateways that restrict unauthorized access to critical functions, even if you can physically access the wires.
Important Considerations:
Safety Critical Systems: Many vehicle functions controlled by the CAN bus, such as braking and steering, are safety-critical. Tampering with these systems can lead to dangerous situations.
Complexity: The CAN bus network is complex, with specific protocols and message structures. Improper interaction can cause communication errors and system failures.
Legal and Warranty Issues: Unauthorized access or modification of a vehicle's electrical systems, including the CAN bus, can have legal consequences and will likely void the vehicle's warranty.
can you control canbus functions anywhere without the diagnostic port

if that does not answer it .. not sure anyone here can


all the best.mark

[metalworker0]

and according to google in all models from 2016

Intelligent Speed Assist: This system uses traffic sign recognition to automatically set the speed limiter based on the detected road speed, which can be configured in the driver assistance menu.

One town gathered millions in a few weeks for installing zone 30 cameras

have you not got any saboteurs

we have them for the emission zones in london - they call them the "blade runners"

all the best.mark

[JanD]

The camera is not present. Also not the wiring. That would not only ask a complete makeover but also a lot of money.

I spent hours with AI. At the end I was teaching AI how it really worked so that lead me to PI, people intelligence. So here I am

First AI does not give any accurate information (watch out!). Secondly. FTC has 3 hs-cans and one ms-can. It all comes together in the gateway.
Thirdly. Noting comes out of the obd. You need a handshake before you can communicate.

Blade runners. I "saw" them on facebook. Maybe we need to invite them.

[metalworker0]

sorry i revert to that when i simply don't know ..

the other thing is "tom tom" satellite navigation .. but you say they are possibly installing these limits faster than that can work

in the UK, don't know Belgium .. they have software add-ons to the satellite navigation systems that know where the speed traps are and are updated by the users daily - the device puts out a sound as soon as you are in the area .

no more advice from me on the can bus as you are clearly leagues ahead


all the best.mark

[JanD]

I use waze intensively but even that is thicky. If you have to drive 1 mile in a 30 zone in the middle of nowhere you automatically drive faster after half a mile. No warnings there except for: "end of camera zone" #tolate.

[JanD]

Meanwhile I stumbled on this. Page 73. https://www.ford.co.nz/content/dam/Ford ... 040523.pdf

I think i can work with this information

[JanD]

Update. HS2-can sniffed and framed. Canable reprogrammed. Buttons 30/50/70 in place. Project works perfect. This topic can be closed.

[Airthies]

Meanwhile I stumbled on this. Page 73. https://www.ford.co.nz/content/dam/Ford ... 040523.pdf

I think i can work with this information

Great you've got a result. Nice work.
Yea the BEMM is a must for any tinkerers there's so much info.
Unfortunately they're soo god they lack the basic info like wiring diagrams

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