P0299 Turbocharger Underboost DTC
 

Been battling this for a few weeks now. Here's the background info:
2005 Ram 2500 4x4 w/5.9l 24v
AFE stg II intake showing NO blockage, MBRP freeflow out back showing NO backpressure.
Bullydog tripledog w' outlook monitor, latest version dl'ed for tripledog.
Normal boost high reading - 21psi
Normal pre-turbo EGT reading - 1400* at WOT and 21psi boost
Normal 75mph level cruise - 7psi @ 800* EGT

Current boost high reading - 10psi w/o cel, 3psi w/ cel
Current 75mph level cruise - 2psi @ 900* EGT w/o cel, Nothing over 65mph w/ cel

Truck is otherwise stock for powertrain, and has been bullet proof and reliable until now. I am a light-footed driver anyways and enjoy high MPG's with this setup.

P0299 cel pops up, puts everything into limp mode. EGT's go crazy and Boost won't exceed 3psi. Erase code, limp mode goes away, egt's still higher than normal and boost topping at 10psi until code comes back with limp mode. Turbo sounds like it's dumping boost. Made a boot for the turbo with air valve and gauge, regulated 15psi input and soaked everything with soapy water, NO charged air leak from turbo to intake. Wastegate linkage can be worked back and forth, no sticking points. ZERO backpressure at down pipe. Freshly reconditioned AFE filter.

Turbo feels good from the cold side, no slop or play, good spin with fingers, looks good, nothing shiny (that shouldn't be), haven't dropped the down pipe to inspect the hot side.

Only guess I have is possibly a faulty MAP sensor? I have unloaded programmer, returned to stock, still throws the code. Might be coincidence, but code usually shows up while attempting interstate on-ramp. EGT's will hit 1250 (my defuel setting on outlook) and keep climbing, and if I don't let out of it I watched it hit 16** and began to sweat.

I did some searching, found some similar problems with other folks here, same truck, same programmer, same situations it seems, but never a fix.

Is the MAP sensor the only thing manipulating the turbo-to-computer communication? Anyone remember how much one of those cost? Maybe know what this thing is supposed to read across a multimeter?

:humm:

Possible Causes:
OTHER DTC’S
INTAKE AIR SYSTEM RESTRICTION
TURBO CHARGER DAMAGED
INTAKE AIR SYSTEM LEAK
BOOST PRESSURE SENSOR
BOOST PRESSURE SENSOR
TURBOCHARGER
INTERMITTENT CONDITION

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1. OTHER DTC’S
Turn the ignition on.
With the scan tool, read the Engine DTC’s.
Do you have other DTC’s?
Yes >> Repair other boost related DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No >> Go To 2
2. INTAKE AIR SYSTEM RESTRICTION
Inspect the air filter and intake air system for signs of restriction.
Were any restrictions found?
Yes >> Replace the Air Filter or repair the Intake air system for restriction.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No >> Go To 3

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3. TURBO CHARGER DAMAGED
Disconnect the air cleaner connection to the turbo charger.
Using the service manual as a guide, visually inspect the turbo charger blades and turbo housing for signs of damage.
Was any damaged found?
Yes >> Replace The Turbo charger.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No >> Go To 4

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4. INTAKE AIR SYSTEM LEAK
Using Miller Special tool # 9022, pressurize the intake air system and inspect for leakage.
Use the service manual as a guide.
Were any leaks detected?
Yes >> Repair leaking intake air system.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No >> Go To 5
5. BOOST PRESSURE SENSOR
Using the scan tool, compare the boost pressure sensor reading with the ambient air pressure sensor with the ignition
turned on.
Are the boost pressure and ambient air pressure sensors within 6 in hg of each other?
Yes >> Go To 6
No >> Replace the Boost pressure sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

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6. BOOST PRESSURE SENSOR
Turn the ignition off.
Install Miller special tool #9022.
Ignition on, engine not running.
Use the scan tool and compare boost pressure reading to the regulated air pressure for tool #9022.
NOTE: The reading on the boost pressure sensor may be slightly lower than the regulated pressure.
Does the boost pressure sensor reading increase with the regulated air pressure?
Does the boost pressure sensor reading increase with the regulated air pressure?
Yes >> Go To 7
No >> Replace the Boost Pressure sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7. TURBOCHARGER
Disconnect the exhaust outlet connection.
Visually inspect the Wastegate flap in the turbocharger turbine housing
Is the Wastegate seized in the open position?
Yes >> Replace the Turbocharger.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No >> Test Complete.

:iws:

Does anyone have an exploded view of the Holsett turbo?

There nothing wrong with your charger , sounds like its the MAP

Unplug it Clean the Connection and plug it back in

Did you find out what was wrong? :pca1:

Double checked the connections, outlook monitor actually plugs in between harness and map sensor, all look good. Funny thing, overhead console display has gone lazy, doesn't power up with ignition, and takes it's sweet time to wake up, sometimes several miles down road before it pops on. I'm going to run through all my fuses and check for bad connections or corrosion. This has got to be a computer/electrical issue. I knew better than to get away from manual diesels that need five or less wires to operate.
:argh:

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Still playing with it. I need to find out what kind of signal the MAP sends out so I can diagnose it without simply buying another to see if it works. With all the fuel expenditure involved in all these hurricane evacuations, my budget is pretty tight right now until things return to normal.

Funny, I always get limp mode on the way TO work, never on the way home. Maybe my truck is trying to tell me something :w2:

Overhead display as in the Outlook Monitor? or as In the Stock overhead Display? Have you tried unloading the Bullydog and monitor? Return the ECM back to stock, unplug the monitor and Bullydog, and see if the problem still exists.. If not, then I would say you found your issue.

Stock overhead display. I have done a complete return to stock including uninstalling the outlook monitor. After confirming that the issue continues in complete stockness... I re-installed the outlook for obvious reasons, so I could monitor boost and egt's. I have not yet re-installed the programmer, and won't until I solve the underboost issue. Egt's are hot enough as they are.

I'm thinking about seeing if anyone local has a boost-fooler I can borrow just to see what effect it has on the issue. If it lets the turbo boost up, that puts me one step closer to just going ahead and buying a new map sensor.

Another member is having the same issue. He pulled the MAP out and cleaned it. Says the code hasn't come back, yet anyway.

Just pulled my map sensor, it's crystal clean, like brand new. Even wiped it on my white Tshirt and it didn't leave a mark. Glad to see it was sealed with an O-ring instead of a gasket. That would have sucked to tear/damage the gasket and not have anything to make another one with!

Oh, and found the problem with the overhead display, it's was a short between the seat and the steering wheel. The outlook monitor takes it's power from a piggyback spade that pushes in with the fuse for the overhead. Evidently I didn't seat the fuse well and it was only getting intermittent connection. Now if only my boost problem will turn out to be that simple.

Well at least you are making SOME progress towards this..

:c:

I've been seriously considering one of those OBDII to PC deals with the software so that I could chart and actively monitor on my laptop everything that is going on in hopes of catching what is happening as the computer decides I need limp mode. Of course the problem there is that I don't have a benchmark to compare to.

I'm used to "this BROKE" and simply finding what broke and fix/replace it. Throw a computer into the equation and you don't know if anything actually broke or not.

I'm glad this is a truck and not an aircraft. Limp mode = falling, NOT slow flying.

More update: Pulled the C-clip off the waste gate actuator rod and worked the waste gate open/closed. Absolutely no restriction. How much headache is involved in pulling the exhaust elbow between the turbo and downpipe? Maybe get a mirror and flashlight and get a good look in there, just in case. Diaphram/spring has alot of tension, too, takes a hell of a pull to get the rod to push towards the wastegate. If I understand correctly, the compression has to overcome the spring rate before the wastegate actuates? If so, the only way the wastegate is the problem, is if it is actually damaged and letting exhaust gas bypass in the closed position.

Intake is SUPER clean. From the filter to the manifold. I'm getting PLENTY of fuel, even with detuned to stock and programmer uninstalled. Where the HELL is my air going?!? I can't seem to put two and two together yet to figure out why I am not producing boost like i should. I am assuming that lack of boost to fuel input is my egt problem since a diesel produces it's heat in rich conditions as opposed to a gasser in lean conditions. I really hope I don't burn something up before I get it resolved. I'm thinking of installing manual boost guages at the turbo and at the manifold so I can 100% verify that i'm not loosing it somewhere in between. Gonna go back out and RE-install my boot onto the turbo and pressure things up again and wet everything with soapy water again.

I've got to be overlooking SOMETHING.

Maybe this stuff will help you a bit. Any progress?

The combination, dual function Intake Manifold Air Temperature Sensor/MAP Sensor (2) is installed into the top of the intake manifold.

The combination, dual function Intake Manifold Air Temperature Sensor/MAP Sensor is installed into the top of the intake manifold with the sensor element extending into the air stream.

The IAT portion of the sensor provides an input voltage to the Engine Control Module (ECM) indicating intake manifold air temperature. The MAP portion of the sensor provides an input voltage to the ECM indicating turbocharger boost pressure.

Just about need something to check sensor parameters. Cummins should have the software and hardware for it. If not, stuck spending $4600 for a Star Scan.

Don't know yet what to do with that info, but I am glad you provided it, did not know that it was also a air temp sender. Wish I could program my outlook to read that info. I'll have to look into that.

As for now, I haven't sat still long enough to recheck my intercooler and boots for leaks, or when I have, i've been so overwhelmed with my interior drywall project, that by the time i remember i need to play with the truck, it's too late and i'm too tired.

It's got to be something simple that I'm overlooking, or it's in the computer (via sender or other). Best I can see, there's nothing PHYSICALLY wrong. I'm just not producing boost properly even though the turbo is spooling up. Again, why I am REchecking the boots and intercooler. Now to get off my butt and go outside and deal with it instead of just clearing the codes and waiting for the fixall to fall in my lap. :w2:

You can check ground, your 5V supply to the sensor and your return voltage to the PCM with that schematic. That would at least tell you if the circuit or sensor is working correctly. You might find something there.

Ahah! That's what I can do with that information! Surely, sooner or later, that would have probably, most likely, maybe dawned on me. My gears are turning slow today. I think. :humm:

Did ya figure out what was wrong? :c:

Closed.

Junkie can re-open the thread if there is still a problem