so about 3 months ago im going to go see my dad.
a code is thrown on my truck and i get it checked first by the local auto zone.
it is a idle air control (IAC) underspeed error
i take it down to the local aamco because ive delt with them sparingly before and its close enough to my house that i can just walk back with no ride.

they "fix" it for $374.
the print out reads
:idle air control motor, fuel injection = $189
remove/replace idle air control valve = $95
another bs hr of labor = $95

alls done and fixed and the guy sketchily says to me "just come back if the light turns on because we might have to order the park directly from ford.."

i think to myself why the hell wouldnt of you done that in the first place?
i call ford. the parts only $127. and they DO have it in stock when the guy says they dont.

i come back from my trip light turns on. go down to get it fixed and cant because theyre "too busy"
play this oh come in on this day and we can fix it/oops too busy tag b.s. for about two weeks. get it in. they say nothings wrong.
hmm fishy..

go another week.turns back on. take it down again leave it there for 3 FULL days and now they say it might be my electrical work or even my ECU. because they cant figure out the problem. but then turn their story and say that it just takes the code a while or so to shut off because the engine has to start and restart so many times to clear it.

now comes to my problem. its on once again and im fed up. its been three months ive been fighting this problem. how should i exactly deal with this. im weary about going down there once more because they might just purposely mess with my truck to get more money out of me in the end.

can anyone tell me exactly what a IAC is, what it does, how it relates to my truck and maybe some pictures. or how i might go about figuring out where it is. ive searched some forums and mainly people just clean them. and theyre as good as new. am i just getting bent over here? please help me out

 

you got ripped off pretty bad. the IAC is a little valve on your upper intake next to the throttle body. not sure how much they cost, but its held on by 2 little bolts. something your could easy replace yourself in under 10 minutes.

 

thanks for the info man.
anyone got pictures?
how is this tied into the ECU and how likely is it to fail and cause a misread?

 

so im getting told that my ecu is possibly faulty because of a misdiagnoses of my idle air control motor.
my truck is throwing a idle underspeed error, and from the "we dont want your money" people at aamco are saying, my trucks ecu is faulty because they have "fixed" what should be wrong. but my check engine light stays on.

how likely is it that my ecu is faulty and how would it throw this code and not others if it is? wouldnt other things be wrong as well seeing as the ecu is the brains of my truck?
no sputters, no spits, no harsh idles, no hard start ups, no missed shifts. nothing. truck runs fine.

help me out guys. my 2nd post! i need some answers!!

 

Got the DTC that the truck has stored ?

BTW : Please don't cross post the same topic in multiple forums.

 

dtc?

 

DTC = diagnostic trouble code.

when you hook up the code reader to the truck what code number is it giving you. an example is P0101

if you dont have a reader try a place like auto zone. its usually free.

 

Merged the threads, redirect left in other location for 30 days.

To answer the question on where :

Part location grid


Actual picture from my 2001, cover is not on the throttle body ( black plastic with 5.4 logo on it ) and the orange colored adapter is from the FIPK. The black on the right of the picture is the TPS ( Throttle Position Sensor )



Sorry about the vague question when the truck illuminates the check engine light, code(s) are stored that point to the source of the error condition.

For the IAC you should have gotten a P0505, P1504, P01506 or P1507.

Usually an IAC symptom is the truck stalls at idle, but there can be a problem where the plunger cannot operate fast enough or too fast ( under / over speed ). Replacing it should have done the trick, if they actually replaced it.

Once you can get the DTC read ( autozone ) get the actual code, not what the Autozone guy says to replace.

One additional question, do you have a tuner loaded on your truck ( Edge, xCal, etc ).

 

IF it's a 5.4L, it's behind the TB elbow, -like SSkully has pictured (nice pics!). You need to post engine size when you need help.

You can squeeze your hands back there to change it, it isn't easy, but it has been done many times lol.

I use a 8mm or 5/16 ratchet wrench.

I get them from Rock Auto for about $60.

__________________

The 98 5.4L -



______________________

It's a little smudged, but here's a pic of an 01 -

 

sweet appreciate it sscully.
its P1507.
i got it back today and aamco said nothings wrong..

sorry for the weak post :/ ill do better next time promise ha
5.4L
and yes i used one at one point. it was a hypertech. not an actual module but more of a programmer.
is says underspeed. so plugged plunger? ha thats ironic..

 

P1507 - Idle Air Control ( IAC ) Underspeed Error

This DTC is set when the PCM detects engine idle speed that is less than the desired rpm

IAC Circuit Open
IAC Circuit Short to PWR
VPWR to IAC solenoid open Air inlet is plugged
Damaged IAC solenoid
Damaged PCM

The IAC solenoid resistance is from 6 to 13 omhs
Disconnect IAC valve and look for no change in engine rpm as an indication of a stuck or damaged valve

Disconnect IAC valve, w/Key on Engine off, measure VPWR circuit voltage at the IAC valve harness connector, should be greater than 10.5 V

Measure resistance from either IAC valve pin to the IAC valve case, resistance should be greater than 10,000 ohms

Remove and inspect IAC Air tubes for blockages ( should be open to Intake ), and cracks ( not sealed tube )

Take a look through these, might want to start with the IAC tube, to see if it is cracked, off the IAC or plugged.

If you remove the IAC, the plunger should move freely.

 

thanks man. appreciate the help.
ill try those out. and figure out the problem.
how would i diagnose a bad pcm? is that a dealer thing?

 

The PCM is on the list as the fall back of items.

If you do not have a tuner loaded on the truck, I would say the PCM is fine.
- Did you return the truck to stock after the Hypertech install ?

Focusing on the IAC and the hose ( shown in jbrew's picture ) is the best place to start.

If the truck is pulsing the IAC and idle is not changing, I would say lack of air is the cause.
- IAC not opening
- Hose to IAC plugged or cracked
- IAC broken or gasket covering the holes in between the TB and the IAC ( guys that said it is fine ).

The CEL if fixed would turn off by itself after 2 drive cycles, so the line the shop gave you is not correct.

 

well the hypertech programmer failed. it somehow glitched and now is broken and will not connect with my truck.

see the truck doesnt pulse at all though. it doesnt idle ruff, or anything like that.
but i will start with the hoses because i have a hunch that might be the problem.
with it being so hot here in az i wouldnt doubt the hoses to crack easily.