Definitive A/C ECU Pinout

[foxdie]

Hi again all,

The following is a pinout of the HVAC (aka Digital Climate) controls fitted to our 8G VR-4s and possibly applicable to quite a lot of other Mitsubishi's as well. I spent an evening piecing together wiring diagrams and have ended up with this.

Last update: 15th February 2012 - revision 2

definitive-ac-pinout-v2.jpg

As I may not be able to edit this post in future, always check for additional updates below!

If anyone feels there's missing information or sees an error, please don't hesitate to let me know and I'll update the diagram

[GalantOnly]

Nice work, Jason

PS: the A-20 is blue/black

[foxdie]

Nice work, Jason

PS: the A-20 is blue/black

So it is, good spot! I had it down in my text notes as blue / black but this got "lost in translation" putting the table together in Omnigraffle

[wintertidenz]

Nice work, I might see if I can eventually get this working in with the CarPC to just have an all-in-one unit.

Although, why are there MUT lines to the air con?! I'm suspecting the engine wire is for telling if air con is on or not, to adjust the idle.

And what's the use of the sunlight sensor?

[crazydriver81]

great work J, have some rep...

[foxdie]

There are MUT lines to the aircon because (presumably) a MUT-III tool can change settings of the A/C ECU such as at what point it turns the compressor on and off in eco mode etc.

The sunlight sensor I believe is to also help estimate how quickly cabin temperature may rise to help it calculate eco mode as above.

[BCX]

from memory, there should be approx 3-4 wires that end up back to the ecu. specifically high/low rad fan, compressor engage, OBD pin 1.

OBD pin 1 isn't L-line - this is the pin that needs to be earthed to put everything on the OBD bus into diagnostic mode (pin 1 can be used for any purpose - not part of the j1962 standard). Mitsubishis use k-line only communication for ECU and TCU - part of the ISO9141-2 standard, except mitsu doesnt adhere to this for MUT communications as baudrate isnt 10.4k and doesnt use default addresses (eg 0x33 for ECU) when doing the 'five baud init' sequence.

light sensor makes the climate control select face vents and bring the blower speed up.

[Mr.Salas]

Hey guys sorry to high jack this thread, just have one question.
What controls the on/off switching of the aircon?
Cause my car is just switch on/off very fast.

[foxdie]

Hey guys sorry to high jack this thread, just have one question.
What controls the on/off switching of the aircon?
Cause my car is just switch on/off very fast.

Can you be more specific? What part switches on and off very fast? Compressor? Condenser fan?

It could be your gas needs recharging?

[Mr.Salas]

Can you be more specific? What part switches on and off very fast? Compressor? Condenser fan?

It could be your gas needs recharging?

The compressor switches on and off like crazy.
The compressor doesn't stay more than 5 second engaged or better said "ON".

At night the A/C works like a champ, but in the afternoon hours it doesn't do the job (The compressor just goes ON and Off).

[foxdie]

The compressor switches on and off like crazy.
The compressor doesn't stay more than 5 second engaged or better said "ON".

At night the A/C works like a champ, but in the afternoon hours it doesn't do the job (The compressor just goes ON and Off).

How odd, if it's literally just night / day, I'd be looking at the sunlight sensor on top of the dashboard...

[Mr.Salas]

How odd, if it's literally just night / day, I'd be looking at the sunlight sensor on top of the dashboard...

Oh ok.
I will cover the sensor and see what happens.

[Reconstructor]

Just a question - why not pin up all "pinout" threads at top, I think they are quite important and useful?