MX83 Cruise Control

**TheDarkRaver** · 08-07-2007, 04:16 PM

Ok I just started unbolting the cruise control system from my Cressida but before I totally remove it I thought I would put the question out there whether I would be able to set up the cruise control to run with a standalone ecu?

I have done some searching around and have found people have been succesfull in retaining the cruise control after engine swaps with std ecu's and also after doing manual conversions, but I have found no info stating whether the cruise control module is a stand alone unit that I can trick by giving it a few dummy inputs?

Just some background its a 7MGTE, R154 manual box and a Wolf ECU..

Thanks to anyone that has any input,

Marc

**CrUZida** · 08-07-2007, 08:59 PM

Cruise control has nothing to do with the factory ecu.

**TheDarkRaver** · 09-07-2007, 04:34 PM

But looking at a wiring diagram of the system there are wires going to the cruise control ecu from the auto trans ecu.. What kind of signal is sent threw this wire (I assume it is just to do with telling the cruise control whether the car is in D etc?)

Thanks for the reply,

Marc

**Dale** · 09-07-2007, 06:28 PM

I have a feeling the signals you need are one to tell the car it is in drive, and the other would be the speed signal (from the ecu, or back of the instrument cluster), the rest should be included in the factory loom... wouldn't you still have the auto trans ecu installed anyway?

**TheDarkRaver** · 09-07-2007, 06:35 PM

No auto trans computer will be going as I have converted it to manual (R154).

And that was the two inputs I figured the cruise computer would need, but am just unsure as all it has on the electrical diagram is input from auto ecu, it doesnt actually say what the input is..

Marc,

**CrUZida** · 09-07-2007, 06:42 PM

http://conceptual.net.au/~peewee/wir...ical%2006a.jpg

ECT, S2 and SP2

S2 is solenoid 2
ECT is ?
SP2 is speed signal

**Mos** · 10-07-2007, 06:15 AM

It also has SP1 (LG-R). Which is interesting - I'm wondering which speed sensor the cruise ECU looks for...?

S2 is, I believe, a method for the cruise ECU to de-select overdrive. By applying power to S2, the transmission will shift from OD to 3rd, provided S1 is not activated (neither S1 nor S2 are activated when OD is selected).

ECT is, I think, the engine ECU telling the cruise ECU that it's ok to run cruise - but I'm not sure and would love if someone could confirm either way (haven't spent enough time with it to find out..).

Mos.

**amichie** · 10-07-2007, 07:16 AM

Originally Posted by Mos

It also has SP1 (LG-R). Which is interesting - I'm wondering which speed sensor the cruise ECU looks for...?

S2 is, I believe, a method for the cruise ECU to de-select overdrive. By applying power to S2, the transmission will shift from OD to 3rd, provided S1 is not activated (neither S1 nor S2 are activated when OD is selected).

ECT is, I think, the engine ECU telling the cruise ECU that it's ok to run cruise - but I'm not sure and would love if someone could confirm either way (haven't spent enough time with it to find out..).

Mos.

Regarding the ECT pin I read somewhere that if the spped drops 5 km below the set point the lock up converter is disengaged. I guess this could be the required signal from the cruise control computer to the ECU/ECT.

**stevevp** · 10-07-2007, 06:18 PM

Originally Posted by Mos

It also has SP1 (LG-R). Which is interesting - I'm wondering which speed sensor the cruise ECU looks for...?

Mos, it reads both the tranny and the instrument cluster speed signals as a safety, if one signal goes out, the cruise ecu raises a fault and cuts out

Originally Posted by Mos

S2 is, I believe, a method for the cruise ECU to de-select overdrive. By applying power to S2, the transmission will shift from OD to 3rd, provided S1 is not activated (neither S1 nor S2 are activated when OD is selected).

correct - mine is switched in the glovebox as the 1uz has enough torque to not need it.

Originally Posted by Mos

ECT is, I think, the engine ECU telling the cruise ECU that it's ok to run cruise - but I'm not sure and would love if someone could confirm either way (haven't spent enough time with it to find out..).

ECT is a signal from the cruise ecu to the TCCS requesting release or application of the torque converter lockup. The cruise ecu will hold torque converter lockup on zero throttle when attempting to maintain the set speed downhill (normally the TCCS ecu would release lockup if the throttle is at idle), and secondly releases lockup to try and maintain uphill speed before asking for OD to be turned off as a last resort

So, to answer darkravers question - yes it should run with an aftermarket ecu - just needs the two speed signals and the neutral switch (leave S2 and ECT disconnected) check the wiring diagram for the manual gearbox optional wiring and emulate that

**TheDarkRaver** · 10-07-2007, 08:02 PM

Thanks Mos, Cruzida and Stevevp for you very heapful reaplies!

From what you have said Steve it doesnt look like it is going to be a problem, so I will leave all the cruise bits in place and have a go at getting the right feeds to the cruise computer to hopefully get it working..

Just wondering which is the netural switch? (I assume this is the one that tells the cruise computer the transmission is not in park or netural) or in the case of a manual transmission the clutch switch?

Thanks,

Marc