First up, I'm the medically inclined boyfriend of said owner of a 2005 Liberty diesel. I'm mechanically intuitive, but was formerly banned from wrenching on *her* jeep because my past failures are as spectacular as my successes. But I'm the contortionist with small hands, so it's now me doing the work. I only know what I read about engines, so Sam's CRD Noob Guide has been very helpful.

We're trying to get the vehicle to pass emissions. It failed the first test because:

1) No catalytic converter, even though the output gas numbers were fine - now fixed, thanks to the outlaws
2) The state doesn't like the elephant hose mod.
3) The state also doesn't like check engine lights either - code read was P0299

We cleaned the MAP sensor and replaced the air filter.
I spliced a as-close-to-stock MAP sensor to mass air hose (thingy name here) with the stump the PO left us. While I was in there I discovered that the mass air hose (or whatever it's called) is separating at the hose clamp where it enters the unlabeled thing (boost control?) under the coolant reservoir that appears to be attached to the vac system.
We cleared out the engine codes and took it for a spin. About 10 miles into it we got a low tire warning and the check engine light (same old code) within a block of each other. Roughly the same time the temp guage started acting like there was a bubble in the coolant system - fluctuating on the high side.

Questions:
Could the tire warning be due to my pushing the wiring harness aside to get at the MAP sensor, ex: at the long plastic box behind the fuel heater? I'm not sure how to access it and check.
Is it safe to assume that the faulty mass air hose is to blame for the P0299 code?
Is there something I'm missing? My old ambulance philosophy is 3 symptoms can be used to triangulate the cause, but I don't know enough about engine respiratory systems or enough about car electrical to spoof sensor signals and make the bureaucrats happy.
I'm guessing that the code isn't a vac system issue - no hissing, loss of power or steering, etc.


Many thanks,
Bumbling Sirenhead

Update: TPWS light mysteriously went out.

IMO, those tire pressure monitor things have never very reliable, on any vehicle.
Ignore the light and use a regular pressure gauge.

P0299?
That's a low boost code right?
If you've already ruled out the MAP sensor, you need to remove and inspect the intake/turbo hoses.
There are three of them.

The first one I think you have already discovered. Its the large hose that runs from the air filter box to the turbo inlet. It is very common for that one to develope a hole or tear.

The second one runs from the turbo outlet to the intercooler. Inspect it for holes or tears.

The third one runs from the intercooler to the engine intake elbow.

After your looked at all those you may consider checking the turbo boost controller.

BTW, I was an EMT for about 7 years.
I enjoy fixing cars more than fixing people.
Cars don't talk back.

Also, have you considered moving to a state that does not require emissions testing?
Might make your life a little bit easier

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U.S. Army Retired

Just curious, what state?

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2006 Sport, GDE FT Eco Tune, Custom Trans Tune
2015 Ram 1500 Big Horn EcoDiesel, GDE Hot Tune