P0299 Woes from Newbie !

tonydunn666 · **Posted:** Tue Oct 03, 2017 10:21 am

Hello All,

Greetings from the UK ! I have a 2007 KJ CRD 2.8 that I would like to ask you knowledgeable people’s opinion on.

My name is Tony, this is my first post on this forum so please be gentle ! I have often used it as a reference and found it a great source of info but up till now I suppose I've been lucky and had no issues with my CRD. However, over the past few months, I've been having issues with the check engine light coming on and the 'P0299' error code. I’d like to ask you all if you might have any ideas I could try before I look at the turbo itself, I’ve a feeling that the turbo itself isn’t the cause because the car just goes too well !

First a bit of background. The car is a 2007 2.8 CRD auto. It has 64000 miles on it. I’ve had it about 2 1/2 years, I bought it from an old chap with 58000 miles on it. He’d had it from new, and whilst he’d always had it serviced he used a local small garage, not a Jeep dealer. Since I got it I’ve spent a lot getting loads of stuff done like cam belt & water pump, transmission serviced, axles serviced, various suspension stuff done, had the original ceramic glow plugs swapped for the 7v eTechno ones, etc to get it just right. The car doesn’t do many miles but does get reasonable trips (20 + miles) fairly often. This problem started at about 62000 miles or so.

I've seen quite a few references to this P0299 code on the forum but my case seems a little different. The car drives perfectly - plenty of power, in fact no noticeable drop in power has ever occurred. No smoke on hard acceleration. No whistling or other strange noises from under the bonnet. In fact if it weren't for the light you'd never know there was an issue, smooth & quiet (for a CRD anyway). This is the second CRD I’ve owned. The first one I had I actually owned from brand new, so I know how one should go & drive, and this one is just as good.

Things I’ve done so far are, I've checked all the vacuum lines and they are OK it seems. I've removed the CAC hoses (still the originals) also and they too are fine. I've replaced the vacuum reservoir tank and solenoid in case they were at fault. I’ve taken the car to the local Jeep specialist (been dealing with Jeeps for many years, where I’ve had the other work done) and they can’t see any issues with any of the vacuum lines or hoses either. I’ve cleaned the MAP sensor following the instructions in Sam’s excellent Noob guide, it was a bit sooty but not excessive.

The Jeep specialist did suggest one possible cause was the turbo vanes sticking and recommended the ‘Terraclean’ process. Was a bit sceptical but I had it done anyway, car did seem to run a bit smoother after that but light came back on after a few days. The turbo does not appear to be stuck – I can move the actuator up & down easily with my fingers – in fact it seems very loose - or by sucking on the vacuum pipe. If I pull the vacuum pipe off the top of the actuator on the turbo at idle I see the shaft move & the revs change, when I reattach the shaft moves back & the revs go back to where they were.

All the filters – main air filter and the small filter dangling from the vacuum tank – are clear – in fact car was serviced just yesterday but light reappeared on the way home after about 30 miles.

Over the time I’ve had this problem, the light has actually gone out itself several times – sometime staying off for a week or more – but then reappears. At all times the car drives fine with no odd sounds, smoke or power loss. There is no change in behaviour when the light comes on. Like last night, when the light reappears it seems to be when you are just cruising along with light throttle, I don’t think I’ve ever seen it illuminate when I’ve floored it. The P0299 code was the only code registered.

After getting back last night I again reset the codes. Today I’ve done a round trip to town – 20 miles, with a 30 minute stop half way. The light has not come back, but I’m sure it will at some point.

Could this be a failed/failing sensor perhaps ? I’ve seen a reference to a software update (TSB 18-007-05) but I think this only applies to cars up to 2005 – or could this be it ? As the car’s never seen a Jeep dealer since new maybe an update is outstanding.

Any clues gratefully received !

Thanks,

Tony

WWDiesel · **Posted:** Tue Oct 03, 2017 12:24 pm

First I would replace the MAP sensor to rule it out! They can go bad! :roll:

Since you have inspected all boost hoses and hopefully the CAC (intercooler) for leaks and found none and you have inspected/replaced parts for the vacuum system for the turbo vane controller and ruled those out, and you have inspected the turbo wheel for any abnormal play.

If the EGR system is still in service, it could be the FCV or EGR valve sticking at times causing lower than expected boost.
Block off the EGR feed tube with a simple thin block off plate you can make out of metal from a soup or vegetable can lid.
See this thread for dimensions :> viewtopic.php?f=5&t=76576

Remove the butterfly plate out of the FCV to eliminate it!
See this thread for instructions to remove:> viewtopic.php?f=5&t=86993

flash7210 · **Posted:** Tue Oct 03, 2017 12:27 pm

p0299 = turbo underboost
This can be hard to diagnose without a proper boost gauge.
Or, if you have a android device, you can get a ELM327 bluetooth adapter and TorquePro app to get a direct reading from the MAP sensor.

I would double check your CAC hoses again. I once had a small hole that was difficult to detect.
Also check the air filter box to turbo inlet hose. Very common for it to develop a hole in in the bottom of it.
After that, replace the MAP sensor.

Just to clarify, the vacuum components behind the air filter box are:
vacuum reservoir- rectangular plastic box that rarely goes bad.
vacuum cut-off solenoid- small solenoid that frequently fails and can be bypassed.
vacuum modulation solenoid- large solenoid with filter stuck in the bottom, absolutely necessary for proper turbo function.

edit: and do as WWdiesel suggested about the EGR valve

tonydunn666 · **Posted:** Tue Oct 03, 2017 1:26 pm

WWDiesel and Flash,

Thanks for your quick replies. Yes, the EGR is still in place - the vehicle is totally stock, no modifications.

The three vacuum components you list - the tank and the two solenoids - yes, those three have been replaced. I do have an ELM327 and the TorquePro app on my phone, that's how I read the fault codes. Are there any specific numbers/parameters I should look at with the MAP sensor to determine if it's at fault ?

I think the next step will be to replace the MAP and see what that does, plus I'll have another look at the hoses.

Thanks again,

Tony

papaindigo · **Posted:** Tue Oct 03, 2017 1:58 pm

If you replace the MAP sensor get the GM one it works just fine and is a lot cheaper than DCJ

WWDiesel · **Posted:** Tue Oct 03, 2017 3:01 pm

papaindigo wrote:

If you replace the MAP sensor get the GM one it works just fine and is a lot cheaper than DCJ

the GM part number is: 55206797
Costs about $20 in US, hopefully you can find it in UK? :wink:

Google part no. :google:

flash7210 · **Posted:** Tue Oct 03, 2017 3:43 pm

tonydunn666 wrote:

I do have an ELM327 and the TorquePro app on my phone, that's how I read the fault codes. Are there any specific numbers/parameters I should look at with the MAP sensor to determine if it's at fault ?

It kinda depends on your altitude.
If you are at or near sea level, the MAP sensor reading should be between 0.0 and 1.0 psi while engine running at idle.
Under hard acceleration it should get to 19.0 - 22.0 psi.
If it doesn't get close to or above 19, you likely have a boost leak somewhere or a bad sensor.

Note: a MAP sensor reading of 0.0 should be about 14.7psi = atmospheric pressure at sea level.
If you were at high altitude the MAP sensor reading will be in negative numbers.

tonydunn666 · **Posted:** Tue Oct 03, 2017 4:06 pm

All,

Thanks again for your replies. Flash - I have done what you describe before, albeit a while ago, and from what I recall the boost pressure was in the range you say. But I will repeat the test now I know the range of numbers I need to check for - thanks for this info.

Thanks also for the part number, I have found one here in the UK for £22 delivered, so I'm going to order one anyway so I can do Flash's test before & after to see if any difference is made.

New sensor should arrive in a couple of days, so we'll see what that does.

Tony

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

Following along here out of curiosity...

WolverineFW · **Posted:** Tue Oct 03, 2017 5:08 pm

Not sure if I missed it somewhere in the thread, but did you check that Mercedes logo sensor on the side of the air filter box? Known to cause issues if loose or has come right off.

Sent from my SM-N910W8 using Tapatalk

tonydunn666 · **Posted:** Wed Oct 04, 2017 4:37 am

Wolverine,

Yes, I have looked at that. Visually seems OK, nothing loose, but who knows, maybe the sensor could have gone bad ?

I'll see what happens when I get the new MAP sensor, if that doesn't help I'll try that one.

At least I'll have a nice pile of spare sensors if nothing else !

tonydunn666 · **Posted:** Mon Oct 09, 2017 1:30 pm

Flash,

My new MAP sensor won't arrive till Friday it seems now ;-(

But in the meantime I've hooked up my ELM327 and monitored the MAP sensor via the Torque Pro app on my phone. I'm at about 400 feet above sea level where I live. At idle the pressure read 14.4, which I believe is atmospheric pressure. Under hard acceleration it quickly climbed to 32.2, then stayed there until I eased off. From what you said, boost of approximately 19-22, it looks like I'm getting a maximum of 17.8 - a bit low, hence the error.

I'll repeat this with the new MAP sensor in place and see what that shows.

Tony

GordnadoCRD · **Posted:** Mon Oct 09, 2017 10:29 pm

Just a few things I haven't seen mentioned, and just want to make sure of..

You may already know this, but P0299 is usually not a code that will self-cancel.
It is an emissions related code that normally has to be manually cleared with a compatible scanner each time.

It's best to also get the DTC instant data when the code was set. (specific MAP MAF IAT, RPM, %throttle, fuel PSI, etc.)
With mine it was off-idle or low throttle when the code was recorded rather than high throttle or maximum boost, even if that is when the light came on. Didn't seem to matter whether hot or cold, however sometimes when cold it happened almost immediately when the trans was put into gear, and the throttle barely touched.

Lacking specific pressure data, the MAP sensor is a good place to start. It will either confirm the data you're already getting with the present one or possibly solve the issue.
{Edit} Where I currently am is roughly 12' elevation above sea level. With engine off and ignition switch on, my MAP readings (new sensor) have varied from 14.5-15.1 depending on barometric pressure, temperature, wind speed, etc.

My EGR/FCV unit has been replaced with the Weeks elbow, but at that time, there was VERY significant carbon crust buildup within the FCV, EGR Elbow, and Intake manifold. Has that been checked?
I installed a Provent to prevent the oil vapor from causing this again. I don't know what options you have there, but a good quality proper catch can of that ilk is very worthwhile.

X3 on the EGR/FCV blockoff. It prevents both carbon contamination and loss of intake charge-air. If you still have original hoses, the most suspect one would be the turbo-to-CAC hose. It deals with much higher levels of heat and oil vapor. Another common place for boost leakage is the corner of the CAC where the pressurized air enters. A leak there usually shows it's self by a buildup of road dust that looks a bit moist or even wet, as the leaking oil vapor makes the dust adhere. It's just inside of where the radiator and the CAC are bolted together.

In addition to restricted intake air, restricted exhaust can also cause this problem. Has anyone yet checked the catalytic converter since this began?
It's life of regular short trips may have built up restriction in the catalyst.

As a 2007, the factory CAC-to-intake hose would be orange silicone lined, and less prone to failure than the early 2006 and prior hoses, although IMO still not as good as the aftermarket silicone hoses. Also a worthwhile investment.

Hopefully the MAP sensor fixes the problem, but even so, a few ounces of prevention.... as the saying goes.

Best of luck.

GordnadoCRD · **Posted:** Tue Dec 19, 2017 11:56 pm

WWDiesel wrote:

papaindigo wrote:

If you replace the MAP sensor get the GM one it works just fine and is a lot cheaper than DCJ

the GM part number is: 55206797
Costs about $20 in US, hopefully you can find it in UK? :wink:

Google part no. :google:

THIS may actually make soaking and cleaning your MAP sensor obsolete.

P0299 Woes from Newbie !

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