Thread: Aftermarket Head Unit - connecting vehicle speed pulse line

Just curious as to what would happen if you simply didn't connect it?
ie. would it nag you, or not work or something else.

Also, have you powered the unit up yet? if so, is there any options to set it up to not use a speed signal?

Originally Posted by AK83

Just curious as to what would happen if you simply didn't connect it?
ie. would it nag you, or not work or something else.

Also, have you powered the unit up yet? if so, is there any options to set it up to not use a speed signal?

Good questions, unsure. There is no further information in the manuals about it.

I haven’t powered the headunit in question up yet. Hoped to do all the wiring properly the first time, then put it in its place and leave it.

Unfortunately the D2’s don’t have a speedometer drive from the transfer box. The speedo head unit gets its signal from the ECU after doing it’s electronic trickery using the signals from the 4 wheel sensors (that are also used for ABS, traction control and hill decent).
I can’t recall anyone successfuly altering the speedo when fitting larger tyres, if you find someone who has they should be able to tell you which wires are used.

Originally Posted by alien

.....
I can’t recall anyone successfuly altering the speedo when fitting larger tyres, if you find someone who has they should be able to tell you which wires are used.

Yeah, there are a couple of units that are capable of doing this.
HunterDi unit is the most easily accessible to us(here in Aus).
I can confirm that the current unit sold by Jaycar 'almost works' ... just not properly enough and not properly enough to avoid it as an option.

Can't recall the wire colour from the BCU, but lots of info on the the topic.

Originally Posted by alien

Unfortunately the D2’s don’t have a speedometer drive from the transfer box. The speedo head unit gets its signal from the ECU after doing it’s electronic trickery using the signals from the 4 wheel sensors (that are also used for ABS, traction control and hill decent).

Yep, I get that, and the output is a 0-12 volt Pulse Width Modulation (PWM) digital signal at 8000 pulses per mile with a 1hz baseline diagnostic frequency. But is that compatible with the headunits vehicle speeds pulse line input?

Originally Posted by alien

I can’t recall anyone successfuly altering the speedo when fitting larger tyres, if you find someone who has they should be able to tell you which wires are used.

Originally Posted by AK83

Yeah, there are a couple of units that are capable of doing this.
HunterDi unit is the most easily accessible to us(here in Aus).

There are plenty of us who have successfully altered the speedo when fitting larger tyre. I am one - I previously had a Truspeed fitted but have the HunterDi fitted now - both units do exactly that, but I'm not sure how/why that's relevant here? I'm talking about aftermarket stereo audio headunits with GPS capabilities from brands such as Alpine or Pioneer not the vehicles speedometer display gauge. An example can be found in < https://www.alpine.co.uk/fileadmin/user_upload/manuals//2018/iLX-F903D/IM_iLX-F903D_EN.pdf > on pages 9 and 10, connection (3):

SPEED SENSOR (Green/White) To the vehicle speed pulse line.

(3) Speed Sensor Lead (Green/White)



Improper connection of the speed pulse line may cause important safety features of the vehicle to fail (such as the brakes or air bags). Such failures may result in an accident and loss of life. We strongly recommend that the installation be performed by a trained, authorized Alpine dealer.

On referral from Alpine who don't handle tech support themselves but instead push it back to their dealers I contacted on and advised him of the specs. The guidance received to this was:

So long as you've actually got the VSS line it will be fine

Originally Posted by twr7cx

Yep, I get that, and the output is a 0-12 volt Pulse Width Modulation (PWM) digital signal at 8000 pulses per mile with a 1hz baseline diagnostic frequency. But is that compatible with the headunits vehicle speeds pulse line input?






There are plenty of us who have successfully altered the speedo when fitting larger tyre. I am one - I previously had a Truspeed fitted but have the HunterDi fitted now - both units do exactly that, but I'm not sure how/why that's relevant here? I'm talking about aftermarket stereo audio headunits with GPS capabilities from brands such as Alpine or Pioneer not the vehicles speedometer display gauge. An example can be found in < https://www.alpine.co.uk/fileadmin/user_upload/manuals//2018/iLX-F903D/IM_iLX-F903D_EN.pdf > on pages 9 and 10, connection (3):

Given I don’t know your set up(or your working knowledge of D2’s) and you are looking for speed signal for an aftermarket radio that would usually connect to an electrical signal usually generated by a transfer box mounted electric drive, read the VSS Alpine mentioned, I thought it was worth mentioning(maybe even if only for those following later on).

Can a signal from your HunterDi be used given you need to manipulate the signal for accuracy?

Originally Posted by alien

Can a signal from your HunterDi be used given you need to manipulate the signal for accuracy?

Yeah, can tap into either the input or output signal from the HunterDi which I have mounted in the dash so not far away from the new headhunt for the signal. That's no issue.

My main concern was if the D2's signal was compatible. e.g. as it's 0-12volts, if the headunit expected a signal up to only 3volts then it could cause internal damage, etc.