DTC 412 Help Plz - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

din0007 · 05-03-2010, 08:17

I'm currently working on my friends 1994 grand marquis with th 4.6 overhead cam.....I'm currently getting trouble code 412 (cannot control RPM during KOER high RPM check)......does anyone know the cause of this or where I should begin my search? thanks in advance

**Bert** · 05-03-2010, 09:10

That code is for secodary air injection systems and yours doesn't have it How are you getting that code? How are you checking codes or what kind of tester are you using? What are the symptoms?

din0007 · 05-03-2010, 09:19

I'm using a innova 3120 scan tool....the vehicle has OBD 1 and the code is 412 and the definition is as posted previously.....I'm unable to really drive the car due to the fact it's not registered yet but from the little I have it seems to lack power and it did fail emmision test...

**Bert** · 05-03-2010, 09:43

Sorry about that. I was thinking P0412.

You could try cleaning the IAC and see if that helps. Clean the MAF with MAF cleaner. See if that helps.

din0007 · 05-03-2010, 10:15

no problem, I've actually already cleaned the IAC along with MAF sensor.....before cleaning both I was also getting a 181 & 189 code (rich adaptive limit at partial throttle right/left side).....this code is no longer present just the 412

**Bert** · 05-03-2010, 13:29

Probably needs a new IAC. It may be stuck.

din0007 · 05-04-2010, 05:46

correct me if i'm wrong but doesn't the IAC only control idle? the idle on the vehicle is fine, since my code is saying it can't control RPM during high RPM check, my logic would tell me it can't be the IAC.....please correct me if i'm wrong, just trying to avoid buying unnecessary parts.....thanks in advance

**Bert** · 05-04-2010, 07:30

The IAC is what opens to give a higher RPM. TRy unplugging it while running and see what it does. Also unplug it before starting to see what it does

din0007 · 05-04-2010, 09:23

well I just got in from replacing the IAC and i'm still coming up with the 412 code

......I did however check the old one by pulling it out and turning the key on and the plunger didn't go to the closed position so I assume it needed replacing anyway......any other ideas? thanks again