AYC help

kevin

Hesitantly Boosting
Lifetime Member
Location
england
First Name
david
Drive
2001 VR4 legnum
hi all,


i have the AYC light coming up after a couple of turns.


a got the (don't know the English word for this) bridge/lift at my garage's to use tomorrow, and so i would like to have as much information possible about the AYC system to help me troubleshoot it and try to fix it.


the AYC lights do work for a couple of turns...


many thanks
 

kevin

Hesitantly Boosting
Lifetime Member
Location
england
First Name
david
Drive
2001 VR4 legnum
thanks,


those things i already checked. fluid OK

errors are voltage and elec pump failure.


i checked all the fuses and they are OK so tomorrow i will check first if the power comes all the way to the pump...

if so what's next? is there a control lead that runs back to the ECU to tell that the power is OK?

might be that there is power to the pump but that the ECU doesn't get the signal trough???


many thanks
 

kevin

Hesitantly Boosting
Lifetime Member
Location
england
First Name
david
Drive
2001 VR4 legnum
hi guys


i did a quick check of the system today and there is no power to the pump (main big black en red wires disconnected)

so i checked the fuses and they are fine.(i think)

could someone tell me where the main power comes from? is it from the ECU or directly from the battery.

where are the fuses located? maybe i missed one...fuses for the pump and valves but for the ECU as well???

does anyone has a electrical lay-out for the car or the AYC system?


thanks
 

kevin

Hesitantly Boosting
Lifetime Member
Location
england
First Name
david
Drive
2001 VR4 legnum
well i got some new information...

i did a series of tests and:

the pump does work when i put 12 volts direct onto it.
with the switches connected to the AYC connector to bleed the system the pump does not work and i hear i small click, sometimes not always when i flick the switch.
however onthe big main connecter next to the pump there is always 10.8 volts???
so where can i locate the main relay for the AYC pump? if i could check if there is 12V i could start figuring out the cabling....

cheers
 

kevin

Hesitantly Boosting
Lifetime Member
Location
england
First Name
david
Drive
2001 VR4 legnum
yes there is the fuse under the bonet (hood) 60amps if i'm correct, if i take that one out the 10.8 volts on the main plug at the pump is gone...
there is a 10 amp fuse i the dash (at steering wheel) which controls the AYS ECU that also is OK. i did not check if the power from that fuse arrives at the ECU, not really clear wich colors are the mains.
i'll have a look at this, this afternoon. do you know where the main relay is? i've got an electrical lay-out of a lancer evo with AYC and there the 60 amp fuse goes straight to a relay and than to the pump, this is 1 straight line...
the plan i got from a evo forum...
 

Attachments

  • aycschematic.pdf
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Dice

1 AYC Bar
Lifetime Member
Location
Gold Coast QLD
First Name
DiceR
Drive
Galant VR-4 2xT25bb
Nissan Cube
I think there is a relay next to the battery near the corner of the front passenger side guard. Mine fell off and became corroded due to water ingress so lucky my mechanic had a spare and replaced it for me.
 

kevin

Hesitantly Boosting
Lifetime Member
Location
england
First Name
david
Drive
2001 VR4 legnum
in deed the main relay is next to the battery at the left headlight... it's a relay that sits in a rubber housing and should be attached to the bodywork... however mine wasn't and so was hanging upside down.
this means it was flooded with water, not really a good match electrics and water so I'm in search of a new relay which is really difficult to find in France (even Europe)
on the rubber housing is marked DENSO 058700-4320 and i found on a Mitsubishi parts site, it's a MR282656 part number... surely mitsu frans had no knowledge of this type of relay...

thank you all in helping to getting to the bottom of my AYC problems...i now understand much more of the system!!!
 
G

Guest

Unregistered
it's a MR282656 part number... surely mitsu frans had no knowledge of this type of relay.

This part number is also used on Evo 4-9 so they probably do have one locally.
 

Grid

Leaving Skid Marks
Location
Poland
First Name
Tomasz
Drive
Legnum 6A13TT, Galant 6A13
this means it was flooded with water, not really a good match electrics and water so I'm in search of a new relay which is really difficult to find in France (even Europe)
on the rubber housing is marked DENSO 058700-4320 and i found on a Mitsubishi parts site, it's a MR282656 part number... surely mitsu frans had no knowledge of this type of relay...

The relay can be opened up and inspected. If your AYC lights work for a couple of turns and then stop it is not the relay that is faulty. The typical failure is the AYC pressure switch. I had the same symptoms as you and I was also checking the relay etc. Ended up replacing the AYC pressure switch (chaps at ClubVR4 have these for sale) and my AYC is healthy for a good 10 months now.
 
G

Guest

Unregistered
Ended up replacing the AYC pressure switch (chaps at ClubVR4 have these for sale) and my AYC is healthy for a good 10 months now.

Actually, the pressure switch on these pumps is one of the least likely parts to fail. I would recommend to only use those aftermarket switches you mentioned as a last resort.

They are only 10 bar rated (with a suggestion to set them at 9 or lower) and the genuine switch is activated at 16 bar pressure. What this means is that your clutch packs in the AYC diff will not operate properly, causing them to burn out prematurely and then you need a whole new diff.

The purpose of those aftermarket switches is to fool the computer into thinking the AYC has reached the correct pressure, when in fact it never does and your AYC never functions properly. If that gets your AYC "working" again, then the pump either has corrosion internally causing the fluid to bypass the pump gears or has a ruptured accumulator bulb diagram.

Much better to repair or replace the pump or pull the fuses and run as an open diff.
 

kevin

Hesitantly Boosting
Lifetime Member
Location
england
First Name
david
Drive
2001 VR4 legnum
thanks guys,
but i'm pretty sure it's the relay, it's all corroded inside and that explains the 10 volt i was getting at the pump...
the diagnostics also told me an electric fault to the pump so lets start with ganging the relay (if i can find one!!!)

by the way what's the difference between my AYC and a super AYC???
 

Grid

Leaving Skid Marks
Location
Poland
First Name
Tomasz
Drive
Legnum 6A13TT, Galant 6A13
Thanks for the explanations. Indeed the aftermarket switch has a hysteresis of 9-10 bar, and the OEM one 10-16 bar so the AYC functions at a much lower pressure. Let me put it this way - when driving on ice etc. it seems to do the job, but I would've expected it to do a better job than it is doing (oversteer still happens quite a lot). I should look into refurbishing the AYC pump and fitting the OEM switch again.
 

Cameron McPherson

#Skids4Jesus
Lifetime Member
Location
Brisbane
First Name
Cameron
Drive
1997 White Legnum VR4
2010 50cc Scooter - Daily
thanks guys,
but i'm pretty sure it's the relay, it's all corroded inside and that explains the 10 volt i was getting at the pump...
the diagnostics also told me an electric fault to the pump so lets start with ganging the relay (if i can find one!!!)

by the way what's the difference between my AYC and a super AYC???

@kevin Did you end up getting a replacement relay and did that fix it for you? I think I have the same issue as my relay is corroded. Got to source a replacement and swap it out and hopefully that will get my AYC working again.
 
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