p1518 intake manifold runner control fault stuck open

[El_Callao]

So my wife was driving my 03 suburban to get some groceries and after she was done the truck started up with that but it showed reduce engine power. After I told to discount the battery and reconnect it and the reduce engine power went away but the check engine light stayed so when she got home I plugged in the scanner and it popped up with that code any help ??

 

[Doubeleive]

it's the throttle body, could maybe just need to be cleaned (if your lucky), try that first and while you are in there unclip the harness and make sure it is clean and no corroded pins or anything, inspect the harness for any chaffed or broken wires follow it from the throttle body back as far as you can looking at every part along the way, sometimes if something is rubbing it can break a wire and cause intermittent problems.

 

[El_Callao]

it's the throttle body, could maybe just need to be cleaned (if your lucky), try that first and while you are in there unclip the harness and make sure it is clean and no corroded pins or anything, inspect the harness for any chaffed or broken wires follow it from the throttle body back as far as you can looking at every part along the way, sometimes if something is rubbing it can break a wire and cause intermittent problems.

I cleaned the throttle body already.

 

[Doubeleive]

I cleaned the throttle body already.

well then usually it's either the harness or the throttle body need to be replaced, usually this kind of problem is pretty intermittent so it makes it hard to diagnose for sure, you could try wiggling/jiggling the harness to the throttle body while it is idling and see if does it, if so then take a closer look at the harness

 

[El_Callao]

well then usually it's either the harness or the throttle body need to be replaced, usually this kind of problem is pretty intermittent so it makes it hard to diagnose for sure, you could try wiggling/jiggling the harness to the throttle body while it is idling and see if does it, if so then take a closer look at the harness

Thank you man we’ll sure do that for sure

 

[Doubeleive]

Thank you man we’ll sure do that for sure

check all the wiring under the hood, look at parts that sit on anything or touch anything where they can rub

 

[El_Callao]

check all the wiring under the hood, look at parts that sit on anything or touch anything where they can rub

You think it could be a ground as well??

 

[swathdiver]

So my wife was driving my 03 suburban to get some groceries and after she was done the truck started up with that but it showed reduce engine power. After I told to discount the battery and reconnect it and the reduce engine power went away but the check engine light stayed so when she got home I plugged in the scanner and it popped up with that code any help ??

Time for a new Throttle Body. I hate those generic code readers. In this case, they are not giving a GM specific explanation, just a generic one.

 

[Doubeleive]

You think it could be a ground as well??

Only if it is on the throttle body harness, probably wouldn't be some random ground. personally if it was me and if I couldn't find any broken wires I would just grab a throttle body from a auto wrecker and swap it out, those guys have them just sitting on shelves by the dozens, take the old one with you and match it up. It sucks to just throw money at stuff but sometimes it's still cheaper than a official diagnostic at the dealer. Is there a chance it won't resolve the issue? yes, but you have start somewhere or just drive it and when it screws up just put in park, shut it off and restart and usually that's gets you down the road until it screws up again. the cel will be lit but just clear it and carry on. you should be able to find a used one anywhere from $30-50 I wouldn't pay anymore than that if they want more shop some where else.

 

[BentleyArnage]

It's not the throttle body. It's the variable length manifold assembly. You may have a hose that's broken or the inside has broken up and isn't moving from low to high RPM setting as it should. On BMW, it's called the DISA valve and they get brittle, break up and mess with the intake valves. On a Ford and many others you have to replace the entire manifold. Don't drive it until you figure it out and correct it.

 

[swathdiver]

It's not the throttle body. It's the variable length manifold assembly. You may have a hose that's broken or the inside has broken up and isn't moving from low to high RPM setting as it should. On BMW, it's called the DISA valve and they get brittle, break up and mess with the intake valves. On a Ford and many others you have to replace the entire manifold. Don't drive it until you figure it out and correct it.

Are you saying that his plastic intake manifold is cracked or something?

 

[Mudsport96]

It's not the throttle body. It's the variable length manifold assembly. You may have a hose that's broken or the inside has broken up and isn't moving from low to high RPM setting as it should. On BMW, it's called the DISA valve and they get brittle, break up and mess with the intake valves. On a Ford and many others you have to replace the entire manifold. Don't drive it until you figure it out and correct it.

Umm an 03 5.3 has no such thing.

 

[Mudsport96]

Are you saying that his plastic intake manifold is cracked or something?

No, he is referring to the dual runner divider that some of the early 4.3 multi port engines had and some of the ford engines had.

 

[Doubeleive]

It's not the throttle body. It's the variable length manifold assembly. You may have a hose that's broken or the inside has broken up and isn't moving from low to high RPM setting as it should. On BMW, it's called the DISA valve and they get brittle, break up and mess with the intake valves. On a Ford and many others you have to replace the entire manifold. Don't drive it until you figure it out and correct it.

don't think these intakes have anything like that, the variable manifold would be on

• General Motors — 3.9-litre LZ8/LZ9 V6, 3.2-litre LA3 V6, LT5 5.7-litre

 

[Mudsport96]

don't think these intakes have anything like that, the variable manifold would be on

• General Motors — 3.9-litre LZ8/LZ9 V6, 3.2-litre LA3 V6, LT5 5.7-litre

Yes the CPI 4.3 had them to switch from a long runner tune port style intake below 3500 rpm to a shorter single plane type manifold above that rpm. Actually worked ok until the stick then they are either real grunty lowend and fall off or no lowend and pull up top. Would have been nice to see hiw they would have worked with the 96+ heads over the swirlport style heads

 

[Doubeleive]

Yes the CPI 4.3 had them to switch from a long runner tune port style intake below 3500 rpm to a shorter single plane type manifold above that rpm. Actually worked ok until the stick then they are either real grunty lowend and fall off or no lowend and pull up top. Would have been nice to see hiw they would have worked with the 96+ heads over the swirlport style heads

that's all beyond me, I just know these manifolds don't have anything like that based on looking at them and if this was the case it would be noted all over and probably make it impossible to swap intake's from say a ss trailblazer or a 5.3 to 6.0 or 5.3 to 6.2, etc that would complicate things a whole bunch.

 

[swathdiver]

Yes the CPI 4.3 had them to switch from a long runner tune port style intake below 3500 rpm to a shorter single plane type manifold above that rpm. Actually worked ok until the stick then they are either real grunty lowend and fall off or no lowend and pull up top. Would have been nice to see hiw they would have worked with the 96+ heads over the swirlport style heads

I had an LZ9 motor, it was great for what it was.

 

[BentleyArnage]

don't think these intakes have anything like that, the variable manifold would be on

• General Motors — 3.9-litre LZ8/LZ9 V6, 3.2-litre LA3 V6, LT5 5.7-litre

You are probably correct, yet the code remains. I would then default to the throttle assembly.