Help, Code 24.

[CAV3MAN227]

-Thanks Josh and yes that makes sense. Today I ran some dedicated black and white IACV wires to the ECU and it still did not change anything. I also did plenty of other things too, checking to see if the Apexi AVCR was hooked up correctly and it is. Looked for broken wires, etc. I cant think of anything else. Guess my next step is to take it to a shop!
-Joe

[CAV3MAN227]

-So today I ended up checking out more stuff and eliminated a couple other things. I also did a D-check run with just the green T's connected.
-In D-check mode, codes 24, 51, and 52 showed up.
-When connecting the 2 black connectors, codes 24, and 49 show up.
-WTF? But the car runs nice just idling around 1200rpms, to high in my eyes of 700-900rpms of what it should be. And still if I ground out the black wire on the IACV it brings the idle to normal and if I ground out the white wire it raises the rpms.
-If anyone has any ideas on this or need more info, I'm listening! Thanks!

-EDIT: Also how can I be throwing a MAF, 49 code if the car runs fine? Afaik, the car would run like crap if at all if there was a MAF problem.

-Joe

[HappyFrog]

I wonder what was meant by code 49 "Use of improper air flow sensor"? I would've expected code 23 to be thrown if it is a faulty maf since there is no fail safe operation related to code 49.

[Legacy777]

Joe,

Grounding those two pins doesn't help indicate anything. You're essentially just keeping the IAC valve at a fixed position. I don't recall, but did you try unplugging the electrical connector from the IAC valve? If so, what did the idle do?

Code 49 is most likely an erroneous code.

[CAV3MAN227]

Joe,

Grounding those two pins doesn't help indicate anything. You're essentially just keeping the IAC valve at a fixed position. I don't recall, but did you try unplugging the electrical connector from the IAC valve? If so, what did the idle do?

-Are you talking about the middle B yellow/red wire? If so I'll check today and let you know between now and this evening!
-Joe

[CAV3MAN227]

-Okay, here is what I came up with, just unplugging just the middle wire did nothing to the idle. Removing all 3 wires still did nothing to the idle!
-For testing purposes:
http://hostthenpost.org/uploads/958eb25 ... f7ef06.jpg
-I removed B for that test.
-Here, I tested @ 20k ohms, A and B read 3.34:
http://hostthenpost.org/uploads/3b40040 ... 351a3c.jpg
-Now B and C. It read 0.01:
http://hostthenpost.org/uploads/7c72856 ... a9a5fd.jpg
-Volts on all 3 were all around 12v.
-Here is a pic of the meter:
http://hostthenpost.org/uploads/afde329 ... 04ac7b.jpg
-Question: when removing the IAC head and putting it back on, is there a special way you have to put the head back on? To me it seems it doesn't matter cause the magnets put it where it wants it!
-Joe

[CAV3MAN227]

-Also... voltage on all three wires (avg.) with car running:
-car cold: white wire: 3.27 black wire: .31 red/yellow 14.20
-car warm: white wire: 1.13 black wire: .02 red/yellow 14.20
-Don't know if that says any thing or if it helps and these were tested with them off the IACV head!
-Joe

[Legacy777]

So you're saying that when you removed all three wires from the IAC valve, it did nothing to the idle? If so, you've found your problem. It sounds like a wiring issue or an issue with the ECU.

Only the middle wire should have 12v on it. The other two wires, to really test them, you need to disconnect the plug from the ECU and test the continiuty of each wire. If they're good, your issue is with the ECU.

Here is the wiring diagram/diagnostics for the IAC circuit
http://www.main.experiencetherave.com/s ... C_Diag.zip

Check continuity between pin 3 on the IAC valve and pin 1 of the F47 ECU connector. Also check pin 1 on the IAC valve and pin 2 of the F47 ECU connector. The meter should read 0 ohms or very close to it.


To note, the reason I'm suggesting the ECU is because when you ground the one side of the IAC and the idle decreases, that indicates to me that the IAC valve is working.

[CAV3MAN227]

So you're saying that when you removed all three wires from the IAC valve, it did nothing to the idle?

- nope!
-So I did your test. With just the ecu disconnected (f47) black and white wires both read 12v at the ECU connector and at the IACV. Also there was .02 ohms for the black and white wires at each end, the IACV and ECU.
-If only the middle, yellow/red, wire is suppose to have 12v, where is the black and white wires getting its 12v source from?

[CAV3MAN227]

-So I once again ran 2 dedicated wires from the IACV to the ECU and I get the exact same results from the stock wiring. Same number and all!
-So does that mean it has to be the ECU? Is it safe to take the ECU apart? If it is the ECU, what are my options? Get another ECU or is the one I have repairable?

-Joe

[CAV3MAN227]

-Another question, with the IACV throwing a CEL, does it mess with fuel, timing, fuel economy, etc. at all? What all does it affect beside high and rough idle?

-Joe

[CAV3MAN227]

-Bump! 2 days!

[Legacy777]

Sounds like the ECU got fried or is not working properly. I know that's probably not what you want to hear, but everything's pointing to that.

[CAV3MAN227]

-Is it repairable or do I have to wait for one to pop up for sale? That's where I was getting at too.
-Is the IACV doing anything to gas mileage, running rich or anything. I was going to try and smog the car Monday. Hope it will pass!
-Joe

[Legacy777]

The quick answer is no, it's not repairable. If you had someone who really knew electronics and had a good knowledge of how this ECU was put together, they may be able to repair it....but that's just a guess.

As for how the car runs....I don't think the IAC valve is going to really cause any major issues if you left it like that for a little bit. I'd be very surprised if it'd pass smog/inspection with a CEL on. That's usually something they check. But maybe it's just emissions they're after.

[CAV3MAN227]

-In Colorado, I think hey passed some law... If you have a CEL they will still test your car. My girlfriend just did her 2000 2.5rs with the CEL on (knock sensor) and it still passed and all. Now a days, CEL can be anything from low washer to a dirty air filter!
-Now I'm just wondering, is the car performing to its standards? Just with a slightly high idle! Like said before, is the IACV affecting MPG, running lean, rich etc?
-Thanks for all your comments Josh!


-Joe

[Legacy777]

No, the idle air control valve just controls how much air goes into the engine. The MAF tells the ECU, and the ECU adjusts for proper fueling. How you're running now is pretty much exactly as if the IAC plug is unplugged. The IAC is completely non-functional. You shouldn't see any issues with fuel economy. What you will see issues with is drivability in traffic, wide varying ambient temperature swings, and other stuff like that.

[CAV3MAN227]

-Okay, thanks for the help! Next step for me is to keep the IACV shut and Swap ECU's and see what happens next. I'll come back and let everyone know what happens!
-Joe

[Legacy777]

How are you planning to "keep the IAC valve shut"? Did you mean by swapping ECU's you'll do that, or where you planning to ground the one side of the IAC valve? If it's the later I would not recommend that as the coil on the IAC is meant to see a duty cycle and not continuous current. It "could" burn the coil out if you do that. Also, there's a good chance that the car won't idle properly during cold startup

[CAV3MAN227]

-No I'm not going to ground it out. Start-up is a little harsh on idle but once its warmed up its okay. i just unloosen the 2 screws on the head of the IACV and turn it counter clockwise to shut it, to keep the idle down. It idles around 900-1000rpms! Then tighten the screws back up!
-EDIT: Slodrive is nice enough to help me out. He said he has a spare ECU we can check with to see it the ECU is truly the problem!

-Joe

[Legacy777]

Good deal. Let us know what you find out.

[CAV3MAN227]

-So with a different ECU in the car cured the code 24 problem. It has the right voltage and works properly. Idle is around 1000 rpms still. But now got a new problem code 41 which I just brought up here on my documentary page: http://bbs.legacycentral.org/viewtopic. ... 5&start=50
-But a different ECU has solved my code 24 problem! On to the next problem!
-Joe