Driving a Commodore cruise control from a Toyota A340 VSS?

[Gus333]

I'm thinking of fitting cruise control to my LX90 Cresta.

A cheap and easy to get option seems to be Commodore cruise control units.

Wiring looks dead simple, all of the smarts are in the engine bay module:
http://forums.justcommodores.com.au/...ol-circuit.jpg

The only catch is likely to be wiring in the VSS (speed sensor) from my A340 box. Does anyone know anything about the relative specs of these?

My guess is that the differences are likely to be:

- Pulse Voltage
- Pulses per km/h

The first would be a deal breaker unless I can whip up a simple circuit to convert the peak voltages.

The second may or may not matter depending on how big the difference is.

Any Toyota gurus have any specs, or know of anyone who tried this? .

(If I decide to test it out, I'll post up my results.)

[thechuckster]

what kind of sensor does the commode use for speed sensing?

or is that getting a signal from the instrument cluster (e.g. the speedo) .. in which case it's might be 0-5V pulse which a VR sensor will not produce at all.

You can use this zero-crossing circuit to convert a VR signal to a low-current 0-5V pulse (goes high when VR signal crosses zero). The VR sensor has polarity and the output (intended for a MSEFI ECU) might be what your cruise control expects. The chip is a LM1815N.


Also (and more importantly) ... that brake switch wiring looks bogus - the two switches (am assuming one is hand-brake and the other is foot-brake) should be in parallel so using either of them will turn cruise-control off. You could also add a switch for the clutch if it's going into a manual car.

[Grega]

the cruise control (well in my VN anyway) gets its input signal from the back of the cluster
it doesn't actually come from the speedo drive.

i think its a divide by 5 circuit that happens in the actual cluster.
there are devices out there for all those folks that do v6 conversions which will replicate this off the speedo drive if that helps.

[Gus333]

Thanks guys, interesting. The cruise module I'm looking at is VN-VS, I think. Maybe VT as well.

Sounds like the Commodore's speed signal is significantly different. Might need to do the opposite of that zero-crossing circuit.

Does anyone know what the speed signal from the Toyota A340 auto boxes looks like? There is a VSS line from the box to the ECU, should be the same as on Soarer/JZX/Celsior/etc (they're all A340 auto boxes.) Google didn't find me anything. May need to measure it myself.

And yeah, you're totally right those brake switches shouldn't be in series on the diagram.

[madmont]

I once fitted a VN Commodore motor and auto into my RN46 hilux.. The commodore ecu needs a speed signal from the commodore dash unit to know when to engage the lockup converter. The pulses were the same type from the Toyota speed signal ( a reed switch in the speedo ) as the Commodore speeed signal. The Toyota speed signal turned out to be twice the rate of the Commodore signal and when the speedo reached an indicated 110KPH the engine immediately cut out due to the speed limiting built into the Commodore ecu. This I rectified by moving the reed switch so it gave half the number of pulses after which it worked as it should. Your Cresta speed signal from the dash may be what your Commodore cruise control needs to work.

[Grega]

Gus if memory serves the modules changes in the VT onwards. they are a smaller unit with different wiring pins. Maybe the same thing, just in a smaller box. Never done the math.

if what madmont is saying, then, if you take the signal from the dash it may well work.

i've got a myriad of original holden diagrams plus am about to take the factory cruise out of my VN (its got its own loom) so i can buzz out wires for you if need be - just let me know)

[timbosaurus]

From VZ on there is not such thing as a cruise control 'module'. Electronically controlled throttle allows the cruise control functions to be done in software within the engine control module.

[ZZT231]

I'm subscribed... I like to do this to my MA61. From my understanding (when I installed it in mum's VN) the speed sensor is 4 pulses from the back of the instrument panel (from memory).

Cheers.

[madmont]

Also (and more importantly) ... that brake switch wiring looks bogus - the two switches (am assuming one is hand-brake and the other is foot-brake) should be in parallel so using either of them will turn cruise-control off. You could also add a switch for the clutch if it's going into a manual car.

There are indeed 2 switches on the Commodore brake as a failsafe

[madmont]

.

i've got a myriad of original holden diagrams plus am about to take the factory cruise out of my VN (its got its own loom) so i can buzz out wires for you if need be - just let me know)

Check if the green wire from the cruise control (speed signal) is connected to the yellow/black wire to the engine ecu (speed signal)

[airfireman1]

The 2 switches on the commo cruise control to disengage it, do run in parallel but both fitted to the brake pedal. there are none connected to the hand brake. Manuals also have a clutch switch. I have fitted several of these units for friends commos. If you are lucky you get the wiring already fitted, mainly thos with a upspec body control module and its all plug and play. Some of the lower spec commos only did not get the harness.

[JustCallMeOrlando]

Have you thought about an off the shelf system for doing this? Plenty of generic ones around.

[Gus333]

I'm well surprised, tons of good knowledge about the Holden cruise control but not so much about the Toyota gearbox signal. Thanks for all the information, though

Have you thought about an off the shelf system for doing this? Plenty of generic ones around.

Yeah, but the good ones seem to be about $350. You can get the Commodore cruise modules for between $30 and $60 on ebay. Even plus wiring, and tracking down a suitable stalk control, I'm still hoping to get the total cost below $100 plus a bit of messing around.

As I said, will definitely document whether or not this works. .

[Gus333]

The pulses were the same type from the Toyota speed signal ( a reed switch in the speedo ) as the Commodore speeed signal.

Cheers mate, I hope that's the case. From what I understand, the A340 is a semi-electronic auto box so I'm thinking it may or may not push out the same signal. Will hook up my multimeter on the weekend and go for a drive (shame I don't own a scope.)

[CrUZida]

Out of curiousity, where is the actuator in that diagram ?