[gidkid]

We love our Liberty turbo diesel. It has 28,000 miles and the only repair has been to the dealer for a glow plug replacement (under warranty). Shortly after we got the vehicle back from the dealer, the CEL (check engine light) came on. It has gone on for a couple of days/off for a couple of days for the last 6 weeks. The code reader shows E401 EGR valve (sticking?). I cleared the code and it has not returned (yet). The factory warranty is over but we have the extended warranty also with a $100 deductable. If the code shows up again, should I have it fixed under warranty or can it be ignored until I have to bring it in for something else?

[sootyjeep]

the code p0401 can be caused by a few things and can be costly. bite the bullet and bring it in.

[JL Rockies]

Your extended warranty is not going to cover an EGR valve the dealer will want $700 to replace. I did the job myself.
After I replaced the valve, the code did not go away. After some investigation, I found a split in the CAC hose. I replaced that and the codes went away. The hose is cheaper and easier to replace so I recommend checking that first.

[revbusnut]

what is the cac hose and where is it

[JL Rockies]

It's the hose you can see on the driver side that connects to the inter cooler to the FCV. Look along the top of the cooler/radiator and you'll see it along top held on by a hose clamp. It travels downwards towards the engine where you'll find the other clamp. It's a lot easier to get to if you remove the Batt. Take it out and inspect the hose carefully, a split can be hard to see especially of it's behind the screen.
The EGR valve itself is $150 but there's a lot a time needs to swap it. I did it myself before I realized my CAC hose was split. I replaced the EGR the the codes didn't go away.
It could also be the FCV valve which is what the CAC hose is attached to. As long as you're there, go ahead and inspect it.

[viperflyer]

P0401 represents insufficient EGR flow. It can be caused by a non-working MAF sensor malfunctioning (I believe it is present in the air-box but not sure), or external air leaking-in (from shot seals or cracked hoses) that could dilute the EGR flow, or some sort of blockage in the EGR valve (from excessive soot build-up) reducing the EGR flow.

[JL Rockies]

Or a split CAC hose

[merlinTec]

Hi
Seen blocked manifold pressure sensor (in the inlet manifold at the back) as well set this code.

[gmctd]

That's the Manifold Air Pressure sensor, also known colloquialy as the Boost sensor, upper rear of the intake plenum adjacent the fuel filter head - remove the 4-wire connector, then the single 10mm hex bolt, pull the sensor and remove the oily soot accumulation with Diesel fuel and a toothbrush - NOTE: do not use the significant other's toothbrush! - wipe the sensor dry, lube the o'ring, install it, see whatchagot

[oudive]

Well my wife got the 0401 code the other day. So as I did the research, I pull what looked like the MAP sensor, it looks somewhat like mine in my 2001 Cummins. Then I noticed the sensore behind it, the 4 pronged one with one screw holding it in. The first sensor (what I thought was the MAP) was clean. The second one I pulled was clogged. It has like 4 little windows and only a portion was open. So I cleaned that thing up and re installed. Used the code reader to clear the code and we will se what happens.

[dieselgirl82]

Hi all,
This is my first post and I am desperate for some help/advice
I have an 05 Jeep Liberty CRD 2.8L diesel. A few weeks ago it started spitting out black and grey smoke incredibly heavy and running through oil (like 4 quarts in 5 miles) I thought this may have had something to do with an oil change place putting in the wrong oil but when I took it back it had run out of oil and they filled it up with the correct oil. I drove it 5 miles after the new oil was in and it stalled out in the middle of the road and died. After waiting for a few minutes it cranked again and got another few yards before dying again. I had it towed back to my place to have a friend who rebuilds cars take a look at it and for a while it wouldn't crank at all. He looked at it and changed the oil again as well as the coolant and he also changed the pressure control valve that connects to the turbo because it had broken and a spring was missing. Now the Jeep will turn over IF it has been sitting a while (it wont crank twice in a row) it may even run for a second or two but then it chokes out and dies. I am desperate because the local dealership knew nothing about diesels and even the couple local diesel mechanics said they don't know much about Liberty diesels. My mechanic friend thinks the turbo is what is causing this but the diesel mechanics both said that was unlikely. I had a friend with an over the counter scanner take a reading and I got several error codes:
P1263 Glow plug 2 control circuit low
P1265 Glow plug 3 control circuit low
P0299 Turbo/super charger under boost
P0102 Mass or Volume Air flow circuit low input

Now after reading the forums I've seen some of these error numbers with different descriptions listed so I am even m,ore confused. It seems like a lot of people have had the issue with black smoke and the engine not starting/choking out but I cant figure out what they did or what to tell my friend to look at. Can anyone help?
Please

[Billwill]

Originally Posted by gmctd

That's the Manifold Air Pressure sensor, also known colloquialy as the Boost sensor, upper rear of the intake plenum adjacent the fuel filter head - remove the 4-wire connector, then the single 10mm hex bolt, pull the sensor and remove the oily soot accumulation with Diesel fuel and a toothbrush - NOTE: do not use the significant other's toothbrush! - wipe the sensor dry, lube the o'ring, install it, see whatchagot

If your MAP sensor still works after this aggressive cleaning I am amazed!

You should not touch it with anything let alone a toothbrush!
Blow it with some carb-cleaner, let it dry and replace it.

The same applies to the MAF sensor which is in the air filter area...also worth cleaning.

And finally, for the OP, there are two CAC hoses...one coming from the turbo to the intercooler up front and one going from the intercooler to the intake manifold...both need to be checked for splits and both should be replaced at the same time..preferably with silicon SAMCO hoses.

You also need to check the hose coming from the air filter and bolting on the the turbo...this short hose, which has the MAF plugged in, is known to fray and tear at the turbo clamp.