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Autotech58, ASE Certified Technician
Category: Car
Satisfied Customers: 709
Experience:  38 years experience in the automotive repair industry with experience with many makes and models.
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suzuki forenza: I replaced the head on a 05 Suzuki forenza

Customer Question

I replaced the head on a 05 Suzuki forenza and now it has codes p0507 and p2279. I have cleaned throttle body and had to clean egr port due to egr flow code. I checked for vaccum leaks and nothing. when I first checked car out I noticed throttle body had open ports checked diagram and looks like they are susposed to be caped off?
Submitted: 4 years ago.
Category: Car
Expert:  Autotech58 replied 4 years ago.

Hi I'm Dave.


With the codes you have, it sounds pretty "cut and dry".

P0507 "Idle Air Control System RPM Higher Than Expected"
P2279 "Intake Air System Leak"


There pretty much HAS TO be a vacuum leak somewhere. It could be a hose that is disconnected or cracked. It could be an intake manifold gasket that did not seal correctly. If you had the injector rails off, it could be an injector O-ring leaking. It could be a bad PCV valve, etc. etc.. The only thing that is certain is that the engine is getting air from somewhere that is not being measured by the mass airflow sensor.


There should not be any "capped off" vacuum ports that I am aware of....put it this way....did you remove any vacuum caps from the throttle body while doing the job?

Customer: replied 4 years ago.

I took on this job after someone else tore it down so I don't know how vacuum ports were or if they were capped. There were 2 ports open with no extra hoses that I can see that are not hooked up to anything. Do you have access to a good diagram because alldata doesn't and the one on the car doesn't show all the ports on throttle body. Is it possible that when I cleaned throttle body it changed the angle of tps and has to much air bypassing throttle plate?

Customer: replied 4 years ago.

Have you had this issue come up before? Would appreciate your help, need to get car smoged.

Customer: replied 4 years ago.

Are you there?

Expert:  Autotech58 replied 4 years ago. computer has gone down several times.....BAD storms!


Sure, I have had similar problems. Deal with this nearly daily on all different makes and models. All I can tell you is that the engine is getting air from some place it is not supposed to be getting air from. I cannot tell you exactly where - because there are too many variables involved here....


What I can tell you is that the problem is not due to any air going through the throttle body as long as it is going through the mass airflow sensor first. This would pretty much eliminate any theory of the throttle plate angle thing causing the problem. The code you are getting (P2279) indicates that the computer has determined that the engine is getting air that is not going through the mass airflow sensor.


The other code (P0507) indicates that the air that the engine is getting is downstream from the idle air control - meaning that shutting the idle air control off fails to slow the engine down. So basically, you are looking for a vacuum leak that will allow air directly into the manifold without going through the mass airflow sensor or the idle air control.


A can of carb cleaner might be very helpful in locating the leak.


Also make sure that all the things that are SUPPOSED to have vacuum have it (Brake booster, purge control solenoid, HVAC controls, etc.).

Customer: replied 4 years ago.

I tried the carb. clean about 5 times not picking anything up. I also found out that three of the ports are supposed to be capped off from a diagram from the dealer. I did found that the pcv hose was in the wrong spot. After that car idles around 850. Scanner says computer is requesting 759.5. I cleared codes and drove it around and there are no codes or pending codes yet.

Expert:  Autotech58 replied 4 years ago.
Sound like you might just about have it whipped....One other way to tell if you got all of the leaks is to look at your fuel trims. If the computer is adding more than about 5% to 7% at idle, chances are you still have a leak somewhere (in a perfect, world the fuel trims would be 0% at idle)
Expert:  Autotech58 replied 4 years ago.

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