# Cam bus wiring help



## CKidder (Dec 12, 2009)

It's called CANBus first of all.  Also, CANBus is supposed to work even if you cut one of it's wires. It runs on wires called CAN_L and CAN_H for low and high respectively. You really need to either cut them both or otherwise mess the signal up by putting a 30 ohm resistor across the two of them. CANBus is, as the name suggests, a bus. So a whole bunch of things will all be hooked up to the same two wires. You will have to find where canbus goes to the ignition and cut the ignition out of the bus.


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## martin19671 (Oct 18, 2011)

Ckidder thanks for your message...... yes meant canbus .....

Basically I want to stop the vehicle from running...mainly the starter from operating.
So you think it will be safe to use a relay? are you sure about the resister?

As the ignition cluster ....like vaux Vectra is a combined unit with one plug and I think at the plug is 3 twisted pairs. coming from it, why have 3 cables? 

For the start signal to be sent I assume the module has to be powered up although a +30 may be there all the time. I have seen what appears to be ignition feed coming out of the plug, but that could be internally done and may not stop the engine from running.

My other thought is the module must have an Earth connection. What if that is removed, then no signal will be sent, but my worry is if that was lost whilst driving it could cause serious problems.

If there is a separate transponder maybe I could do something there?

Do you have any other ideas?


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## madmike8 (Jun 16, 2011)

Why not use a contactor across the starter wire? Seems simpler.


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## CKidder (Dec 12, 2009)

A contactor across the power wire to the start solenoid could work. Otherwise, I'd bet it would work to find the power wire to the ignition and cut that. It can't send out canbus signals if it's not on. Either way, it appears cutting a power wire of some sort would be the simplest way.


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## martin19671 (Oct 18, 2011)

I have had no choice so far on vehicles with canbus for starter motor but to run cables outside to starter motor solenoid, the problem I have found is you try running cables to under the bonnet from the inside these days. Take a Renault Espace, with the credit card ignition with push start....its almost impossible to get cables to the outside., and it can be difficult getting to the starter wiring to cut.

Well I might try cutting a twisted pair and see what happens. I doubt the ignition +15 coming out from the module would do anything and not affect the starting, as I bet the powering up of the control unit is done internally. and the +15 is for something else.

My problem is more and more cars will be like this


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## frodus (Apr 12, 2008)

why not buy an immobilizer that is built for the vehicle?


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## martin19671 (Oct 18, 2011)

I am working for a car finance company and they lend money to people with bad credit history for buying a car. I have to fit these units. Every Month when the customer makes a payment they get sent a text message with a pay code. They enetr this using the supplied Remote control.

No Payment = Vehicle immobilised after a few days, car finance company repossess vehicle.

The technology is great if it been 15 years a go before canbus


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