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Discussion Starter · #1 ·
A freinds Accent is throwing codes P0068 and P0505. They just had new plugs and coils installed but engine is still idling a little rough. From what I gathered it could be the MAP sensor, IAC valve, or the TPS. Maybe all 3? The car has around 125K miles, so I'd figured this would be a good place to ask for advice. Thanks!
 

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A freinds Accent is throwing codes P0068 and P0505. They just had new plugs and coils installed but engine is still idling a little rough. From what I gathered it could be the MAP sensor, IAC valve, or the TPS. Maybe all 3? The car has around 125K miles, so I'd figured this would be a good place to ask for advice. Thanks!
P0068 is a correlation fault between the MAP and TPS signals. That is, the ECM is comparing manifold pressure against the position of the throttle plate and is not seeing what is expected (e.g. throttle plate is closed and manifold pressure is high or vice versa). The P0505 seems to be some kind of generic IAC fault in that the ECM can't properly control idle speed. Does the engine have a high (or low) idle? Also, have you checked for vacuum leaks? It could also be the IAC valve is sticking.

Before throwing parts at the problem, check for vacuum leaks. Then, remove both the throttle body and IAC valve and clean them thoroughly (be sure to clean the passage through the throttle body that goes to the IAC valve). Put them back on the engine, clear the codes, and see if the condition improves and/or if the codes come back. @Red Raspberry made a thread a while back where he took his IAC apart to clean it. If he sees this thread maybe he can post the link.

If you have a scan tool that read live data then you can also check the MAP and TPS PIDs to see if they look normal at idle and when revving the engine. At sea level, you should see a manifold pressure value somewhere around 9-13 in/Hg at idle with engine warmed up (no loads) and as throttle increases to 100%, pressure should increase to roughly atmospheric pressure.
 

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Discussion Starter · #3 ·
Ok I'll check and try cleaning the mentioned sensors. I assume MAF sensor cleaner would be safe to use? I haven't driven the car yet but she reports that sometimes the idle will drop low and almost stall the car? Thanks again!
 

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Ok I'll check and try cleaning the mentioned sensors. I assume MAF sensor cleaner would be safe to use? I haven't driven the car yet but she reports that sometimes the idle will drop low and almost stall the car? Thanks again!
MAF sensor cleaner would be fine (although expensive for this purpose). You can also use carburetor or brake parts cleaner, but in any case just be careful you don't allow the solvents (and dirt/debis that is loosened) to get into the electronics.
 

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Ok I'll give it try. I have both but didn't know if brake cleaner would foul any of the electronics. Are gasket needed after taking them off? Just trying to do this a cheaply as possible cause she was charged nearly $900 for coils and plugs ☹. Thanks again!
 

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Ok I'll give it try. I have both but didn't know if brake cleaner would foul any of the electronics. Are gasket needed after taking them off? Just trying to do this a cheaply as possible cause she was charged nearly $900 for coils and plugs ☹. Thanks again!
Throttle body gasket is paper so it may tear when the throttle body is removed. Should just cost a few dollars, but may take time to order. IAC gasket is metal (if it's original) so it can be reused if you don't damage it.

$900 for coils and plugs on these cars is robbery. If she had that work done to correct this problem, she should talk to the shop owner and ask for at least a partial refund since it did nothing to solve the problem. If she goes to repairpal.com, she can get an estimate of what shops are charging for that work as evidence she was overcharged.
 

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Discussion Starter · #7 ·
Oh I definitely agree. The place is scam and I imagine they had cake and ice cream after she left lol. Thanks again! I'm going to take a look at it on Monday, but if you have anymore tips feel free to let me know!
 

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2008 Accent 3 dr 5 sp manual; 2010 Genesis Coupe 2LT track 6 sp manual
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The IAC is easy to clean on the Accent. It gets carbon and sticks. It's a cylinder with a window that is turned to vary the air flow.

But IIRC it's only two bolts and it can only go back together one way.
 

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Discussion Starter · #9 ·
Can a MAP sensor also be cleaned like MAF Sensor? I know on my Mazda the MAF sensor has to be cleaned every so often or I throw lean codes. I didn't know if the Accents MAP sensor could be cleaned the same way? Thanks!
 

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I've got over 180k miles on my OE with no cleaning. It has a tiny hole that may get clogged I suppose with oil if you have a lot in the intake.
 
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