Phildodd06

I am getin this error code any info on how to diagnose the actual problem as the ISCV are like £300 new

24, i have read the code through my laptop and it its '24 open/short in ISC valve circuit'

The car is a Version 5 STI Type-R 1999
In pretty standard condition, only mods are
Decat
Green cotton
Oil catch tank
Version 9 crank
uprated oil pump

heres the problem...
I have no running issues what so ever, the car idles perfect, responds streight away, runs sweet as a nut
The check engine light only flashes when i down shift using engine braking.
If i shift down a gear and slow down the check engine lights up and will stay on untill i either dip the clutch and let the revs drop down to 1000 or select neutral and let the revs drop down to 1000, after doing so the light goes out.
When the light is on, there are still no running issues other than the light being on.
However, if i drive and dont engine brake, the check engine light wont light up
It has been like this since buying the car over 2 years ago, and since then i have had a full engine rebuild and the problem is still there.

I am now geting fed up of not being able to engine brake and hear the exhaust burble

Any help would be much appreated

STI_Baly

iTrader: (23)

Change the ISCV not necessarily for a new one but try a functional second hand one or if a mate has a similar car swap his over to try and see if it makes any difference.

I'm assuming the electromagnet has become a bit weak with wear and tear therefore malfunctions when you engine brake due to the sudden change in revs therefore creating additional pressure. (This is only an assumption mate)

Phildodd06

Yea sounds possible, thanks bud.
Dont know anybody with another impreza tho. like you say i try it for a week or so to either diagnose it or elliminate it.

Anybody else got any other sujestions?

STI_Baly

iTrader: (23)

I'm not to sure if the ISCV's are all the same on the V1's to V6's. If you PM me the details on your ISCV i can check some of the ISCV;s i have here and get back to you.

If i have it you could have it for £25 inc P&P. Let me know either way.

Splitpin

See your other thread re the data monitoring Phill.

I wouldn't replace the valve yet. If you're still experiencing problems with it the first thing I would check is that there's no condensation/corrosion in the plug. If that checks out, it's worth doing an electrical continuity check between the four control pins in the plug and the other ends in the black (I think) ECU connector.

Might be worth removing the valve and seeing if it's gunked/carboned/oiled up too. A clean might sort it.

If you do try another valve, you can use one from any other 99/00 car (i.e. 99/00MY Turbo 2000, or STi 5/6). None of the other types will fit.

Phildodd06

STI_Baly
Thanks for your reply, ill keep you in mind for if i do need 1 =)

Splitpin
Thats a good idea, would i need any pin data tho to find the wires at the ECU side of things?

Altho thinking of that, a continuity test will only show up a complete break in the wire, and it that was the case surly it would either not work properly or have the CE light on constantly.
Does that make any sense to you mate?

Splitpin

Yes, you should find that in Slipstream_UK's technical manuals thread, if and when the time comes.

Not necessarily. A continuity test may show up an intermittent connection that drops in and out with a bit of wiggling around of the cable, or it may show a measurable resistance. First things to look at though are the connections inside the plug itself. It should be sealed - so the contacts should be pristine. Also worth pulling the valve and checking it isn't gummed up. If it can't move freely it'll draw too much current.

There are actually two separate error states in the ECU program that will cause the "24" code. IIRC ECU Explorer isn't clever enough to tell them apart, but have a look see if you can use it to manually monitor memory offset 0x80106F. If you can, tell us what the value at that address is.

STI_Baly

iTrader: (23)

Courtsey of Jollygreenmonster find the ECU pinouts at this link (at the bottom for your car).

JollyGreenMonster.co.uk

Phildodd06

Right done some more testing this evening,
I got the CE light back on while i had the Laptop connected, checked the steps with some live data, this was what i have after a few mile drive....

Idle Speed Control Valve Step Minium 11.00 Current (At idle & all eletrics off) 16.00 Maxium 112.00

Also checked Idle control valves, for and dirt, but was fine, gave it a clean out with some brake cleaner while it was out.
All connections seem fine on the plug too.

This error code came back '24 open/short in ISC valve circuit'
it was in the current section of the error codes while the CE light was on and when it went out as my RPM droped too 1000 it moved inyo the Historic section.

I need to try the continuity test next but will have to do that on sunday as im really busy atm, i dont think im going to find anything there tho tbh but ill still give it a bash, any idea what Resisdence i should be getting from ISCV plug to ECU plug?

Phildodd06

Thanks for the Pin data link BTW