Got my Evo last week, and the ASC light would pop on after about 2-3 minutes of driving. Weather has been in the 30's and 40's in that time. Well this morning when I got to work it was 5 degrees, and was just following a foot + snow fall last night. Driving to work it was the first time the ASC light never came on, and I was able to select the Tarmac, Gravel, Snow setting. I figured my ASC pump was shot, but this gives me hope that maybe it was just an ECU error that seems to happen to some Evo's, but the unit is actually fully functional.

Should I bring my car to Mitsu and have them check the ECU? I wonder if I take it in for the ECU flash recall if that would fix the error. Any other ideas on how it could have magically fixed itself?

 

If they have a recall for your car then I would take it in anyways and tell them about what's been going on.

 

Well when I left work last night I checked the reservoir level and saw that it was about an inch below the min line (after the car was sitting for 9 hours on a level surface). The service light popped back on when I was driving home. I added some ATF to the reservoir last night.

Today when I drove into work I checked it, and again it was bone dry. I know it isn't leaking because there are no atf stains under my car, so I'm guessing that there is air trapped in the lines because whoever did work on my car before I bought it must have disconnected the lines or something and never properly bleed the system. This is why I hate buying used cars lol.

 

My ASC light didn't pop on this morning and was able to drive for 10 seconds before it appeared and stayed. This hasn't happened since it initially started showing up over a month ago, when the temp dropped below freezing for the first time in over a year.

 

Okay well I just checked it now since the car has been sitting level for about 5 hours now. It looks like I didn't fill it up enough because it's right at the minimum line (before it was about 1" below that).

Is it normal for the reservoir to be nearly empty after the car has been driving for 30+ minutes? I might just save myself the headache and just take it to mitsu and have them bleed the system. I just don't wanna kill the pump if I can help it lol.

EDIT: Can anyone confirm this method works for bleeding??

https://www.evolutionm.net/forums/ev...oise-rear.html

 

It is not unheard of for a nearly-dead pump to not fail at start-up when it's cold. The working hypothesis is that the thicker fluid can't get around the plate in the pump, so the pump actually manages to achieve pressure. Then, as reported above, the pump fails a while later when some of the pressure is used and the now-thinner fluid can get behind the plate, so the pump can't get back up to pressure.

Mine did this for a few months late last winter.

I have not heard of any reflash "saving" a pump that has gotten to this point.

 

The weird thing is it'll be fine the entire hour commute to work. I think this weekend I'll give the bleed method a shot. We'll see when I drive home tonight if it'll continue working now that I've added more fluid to it.

 

If you never hit the gas hard, you'll never use any of the pressure in the bulb. Next time it seems to be OK at start-up, use the go pedal a bit - within reason and local laws, of course - and see what happens. The easiest way to know if you're using pressure is to switch the dash display to the S-AWC graphic.

 

Awesome... thanks so much for the tips. You've helped me with a few things since owning my Evo, so I wanted to say thank you.

 

No, thank you for giving me the chance to raise my signal-to-noise ratio.

 

Well as always you're right Iowa lol.

First off the S-AWC dash gauge wasn't filling up at all, and when I was coasting about about 15MPH and gave it 3/4 throttle the service light came on again. Looks like I'll be replacing/resealing the pump in the coming months lol. Watched a video on here that showed how to rebuild the pump, and also a $200 kit with all the parts, and it doesn't look all that bad. Though I may just save the hassle and replace it with a new OEM unit.

 

My acd appears to have magically fixed itself. 3 start ups and no CEL


Fingers crossed.

 

Check the S-AWC gauge to see if it is building up pressure. I thought mine was fixed until I checked the gauge to see that it wasn't building pressure, plus when I did a second gear pull it popped back on.

 

Pressure is building! It lives!!

 

Update: looks likes it's building in gears 1-3, can't get a response in 4 & 5.

I am now getting a different CEL, however.