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Intermittent P0299

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Trying to diagnose an intermittent P0299 on my own vehicle, cannot tie the truck up at the dealer at this time. The truck is an 05 F350 (04/05 build) and the code usually will only set when pulling my 9000 lb trailer. I do not have an IDS to do all the KA tests but the freeze frame captures on my scanners show that the problem usually occurs at 55 mph, 1600 rpm, 40-50% throttle and 70-80% load, usually cruising or lightly accelerating in high gear. I have pulled the EGR and it was clean, only a slight amount of soot. Driving with the scanner in snap shot mode yield no info because it did not act up today.

 

Any 'best guesses' from those of you who are working on these engines every day? I don't suspect the turbo at this time because one FF capture showed the code set at idle. Seeing any pattern failures? Thanks for the help.

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I've been "drawn away" from much in the way of 6.0 diag for several months.... P0299 without any other "helper" codes is going to be gnarly but I might consider starting with the EBP sensor as a distinct possibility... Any intake or exhaust mods?

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Seems to me that would be the most likely cause and I agree with Jim, "without helper codes" it's hard to say if anything else is affecting the turbocharger. This would be a great time to make use of a VDR...

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One of my freeze frzme captures showed the engine was at idle when the code set but I was exiting the freeway when the MIL came on. Can't remember if a FF snapshot is taken at the end of the event or the beginning of the event. If the snapshot is taken at the beginning of the event I can rule out a sticking turbo.

 

The last time the code set there was a slight delay in the build up of boost but I was lightly rolling the throttle on after coasting going down a slight grade and climbing another, I attributed it to turbo lag.

 

I never have a problem making boost under load, if the turbo were sticking would it not also stick in a position that would effect boost (either too little or too much) above 1600-1800 rpm? This code always sets at low rpm.

 

I'll try an EBP sensor first, a quick and cheap 'first shot' for shotgun diagnosis.

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I just repaired a truck for this exact concern. Everything passed, boost test, VVT test, EGR test, etc, etc. They only caught the check engine light while towing a trailer.

 

Called tech hotline, and engineer advised me that he suspected the variable geometry business binding up under the extra heat produced by working the engine harder with the trailer attached. I took the turbo apart and found the CHRA assembly somewhat rusty inside. I cleaned up the unison ring, and found it pitted, so I replaced the turbocharger. Again, all the testing passed, but the truck seemed to have marginally more power on the road test when I was done. We'll have to see what happens there, but I'd pull the turbo on yours and have a peek inside.

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Exhaust temp is usually 1000-1150 when the MIL or pending code P0299 sets. If I keep T/H on and the RPM around 2200 RPM the exhaust temps stay around 800-900 and no problems.

 

You all have convinced me to check the turbo. Don't know if I will do it myself or have it done under warranty-I hate 'learning' on my own vehicles. Either way the repair won't happen until the end of May, I'll report back with the results.

 

Thanks for the help everyone.

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With the advent of tsb 08-04-07, diagnostics are to the point. All the ones I have seen with this code have led to the turbo right away which is good because it only pays between 3 and 4 hours. That includes all the steps involved when your not wrenching on the vehicle (time at parts, digging the truck out of the parking lot, ect.) Not a lot of time for gettin a coffee.

 

On a side note I have put chra's in all but one with out any problems so far.

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I also agree with the turbocharger sticking. I have done quite a few where people bring them in with check engine lights with a P0299 and they report no driveability concerns. Upon tear down though you can clearly see the turbo is the problem.

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What is a chra? I have decided to have the work done under warranty, if there is an internal problem with the turbo (unison ring etc) and it has to be replaced then all of my work will be for not since I work at an independant shop.

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