P006D -- 2020 EcoDiesel

[Diesel85]

I got a P006D Barometric Pressure - Turbocharger/Supercharger Inlet Pressure Correlation code on my 2020 EcoDiesel.

I tried replacing the MAF sensor thinking that was the culprit. Did not fix it and I returned the new MAF sensor so I didn't lose money. Reinstalled original.

Along with checking the air intake hoses and CAC hoses for tightness. I did not pressure test the system. I'm also using a genuine MOPAR air filter right from Geno's.

Code is repeatable. Cleared the code and it comes back after about 3-4 starts/stops. No cool down/warm up cycle needed.

Truck is getting the usual 27-29 mpg for my commute.

Looking for someone to take a stab as to where to look next. Maybe the MAP sensor? MAP sensor always shows 28.7 inHg when the truck is turned off. The MAF sensor is showing 31 inHg and the Turbo Baro sensor is showing 29 inHg. Not sure if that MAP sensor is way off showing 28.7 inHg with the truck turned off.

Attached is the freeze frame data.

Also, the truck is under warranty, but if I can fix it myself for a cheap sensor problem, I'd rather, because I get satisfaction out of it and I learn a lot. Not going to take half the engine apart to fix it or disturb more things that would cause flags. If it's in my face, then I'll do it, otherwise, I'm leaving that for RAM to figure out.

Some folks said I already did too much troubleshooting for a warranty fix. I have it scheduled on 8/8 for it to be looked at.

 

[bcbender]

Well... Can you measure the actual pressure with a stand alone or test manometer? Seems like one is not measuring accurately, you said you changed the MAP and it did not change so maybe the Turbo Inlet is low? Without knowing what the actual pressure is outside, its hard to say which is off. the code is for correlation so its valid as they do not agree. Engine "OFF" the two sensors and a calibrated external manometer should in a perfect world all agree..

 

[bcbender]

Without knowing your engine layout, Id assume the Baro pressure to be MAP not MAF, and its interesting there are two turbo inlet sensors listed there, A has a value and B is zero, maybe its not used on the ECOD?

EDIT :The MAF sensor is showing 31 inHg and the Turbo Baro sensor is showing 29 inHg. Not sure if that MAP sensor is way off showing 28.7 inHg with the truck turned off.[ MAP is Manifold ABS Pressure / MAF is Mass Air Flow ] for those wondering.

 

[bcbender]

The MAF sensor is showing 31 inHg and the Turbo Baro sensor is showing 29 inHg. Not sure if that MAP sensor is way off showing 28.7 inHg with the truck turned off.

Sorry, in my last post it got me thinking did you use the wrong terminology or did you swap out the MAF sensor? On your data sheet, the MAF is zero (as it should be Engine OFF) and its the MAP and Turbine inlet A that are not in agreement.

 

[Diesel85]

@bcbender: Thanks for replying back and providing help.

To be clear: I swapped the MAF (Mass Air Flow) Sensor on the intake (by the air filter) because it was right in front of me.

When testing, the outside/ambient barometric pressure was 31 inHg. Verified with my weather station and with NOAA.

The MAP (Manifold Air Pressure) Sensor is on the manifold on the engine mounted way in the back.

It wouldn't be an easy task to get a manometer on this engine without getting creative.

Today I did hook up my smoke machine to see if I could see any evidence of a leak. I took the hose off the filter box, and got my cone adapter and sealed it on. Saw no smoke from any of the joints/connectors, including wiggling them around. Ran it until I saw smoke coming out of the tail pipes. I understand that does not really compare to putting 20-30 lbs of pressure in the system, but I figured it was worth a long shot.

I agree with you in regards to the values being off on the MAP and Turbine inlet A not being in agreement.

I'm leaning more towards a sensor issue than an actual physical issue.

I'm also wondering if it is the MAP sensor all carboned/sooted up causing a bad reading. The EcoDiesel is notorious for gunking up the intake manifold due to the EGR.

Kind of want to just leave it be at the point and see what RAM has to say about it.

 

[bcbender]

When testing, the outside/ambient barometric pressure was 31 inHg. Verified with my weather station and with NOAA.

That is what I meant by a manometer, not one on the engine but one to verify actuals.. Seems like your MAP is reading accurately but the turbine sensor is low. I would agree that it seems to be a sensor issue as it cropped up suddenly, and would totally let RAM deal with it. Lets see if our assumptions prove correct.

Cheers!

 

[sag2]

This indicates it is most likely the MAF/IAT/IAP sensor you replaced, but if you look at your freeze frame report the Baro (32) and MAP (28.7) are not the same. KOEO I would expect them to be the same. I would want to verify actual pressure against ECM reported pressure. It could be wiring, but the MAF info is LIN bussed to the ECM. Perhaps there is a voltage problem with the MAP sensor? Just guessing out loud.

Set Conditions:

• The PCM detects a plausibility error between the Inlet Air Pressure Sensor Signal and the BARO Pressure Sensor Signal for 4.0 seconds.

Default Actions:

The MIL will illuminate.
Possible Causes

MASS AIR FLOW/INTAKE AIR SENSOR

POWERTRAIN CONTROL MODULE (PCM)

 

[Diesel85]

This indicates it is most likely the MAF/IAT/IAP sensor you replaced, but if you look at your freeze frame report the Baro (32) and MAP (28.7) are not the same. KOEO I would expect them to be the same. I would want to verify actual pressure against ECM reported pressure. It could be wiring, but the MAF info is LIN bussed to the ECM. Perhaps there is a voltage problem with the MAP sensor? Just guessing out loud.

Set Conditions:

• The PCM detects a plausibility error between the Inlet Air Pressure Sensor Signal and the BARO Pressure Sensor Signal for 4.0 seconds.

Default Actions:

The MIL will illuminate.
Possible Causes

MASS AIR FLOW/INTAKE AIR SENSOR

POWERTRAIN CONTROL MODULE (PCM)

Thanks @sag2

So re-reading AllData, it doesn't mention anything about the MAP sensor, just the MAF sensor. I already replaced it and I did the K188 jumper test this evening and I did not get a CEL for P012D-00. Which makes sense, because when I replaced the MAF sensor, the P006D didn't go away.

Shooting down to step 4, check the wiring and PCM.

It could be a wiring issue or it could be the PCM. But if it was a legit wiring issue, wouldn't I get other codes?

Strange that it's all of a sudden. I also find it funny that in step 4 it says if the P006D DTC returns: Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.

Has to be the shortest DTC diagnostic. lol

I attached the P006D flow chart.

 

[Ozymandias]

Did you perform a hard reset?

 

[Diesel85]

Did you perform a hard reset?

Hard reset, meaning disconnect the battery for like 20-30 minutes and then reconnect? No, but it's funny, I was thinking of that earlier. With all of the stuff I read on here about doing battery resets. Very plausible.

I followed the wiring diagram for the MAF sensor. I checked the ground (on the top of the right fender) to the ground pin for the MAF. Checked out great, 0.001 ohms. I then checked the pins just in case and I cleaned them with contact cleaner. All look great. The grounds look perfect. I did loosen them and retightened them for the heck of it. I also checked for 5v and I am getting 5.12 volts.

I am not going to undo the PCM in fear of bending pins. If I was out of warranty, I would start touching that, but no way am I touching that PCM in warranty. But now after testing, I really don't think it's a wiring or corrosion issue.

 

[Diesel85]

Before doing a hard reset like @Ozymandias mentions, I put it all back together and I decided to grab some data after cleaning the MAF connector and tightening the grounds on the right fender. I see that my Baro and my Turbo closely match:

@Ozymandias -- Do you think I should still do a hard reset at this point?

 

[Ozymandias]

I can't be bad to do so, a restart of the whole system is always a good way to get rid of "accumulated" trash.

 

[bcbender]

Agreeed.. These trucks are rolling supercomputers now and need an occasional CTRL-ALT-DEL to get them strait...

 

[Diesel85]

I will clear the code and reboot this morning, and report back after doing some driving around.

Thinking about it this morning over some tea, and re-reading the P006D testing procedure along with the wiring path diagrams, it's not a hard thing to test unlike reading through some of the other P-codes as I was perusing around the service manual.

@Ozymandias -- Thanks for the suggestion on the reboot. Fingers crossed!

 

[Diesel85]

So I rebooted it and test drove it and the code came back.

While I was sitting in the garage playing with the app, I had the data logger going. I noticed that the Baro sensor was showing 29.5 inHg and the MAP was showing 29.0 inHg, but it was going back and forth every second to 28.7 inHg. Like it didn't know what it was reading.

I'm really starting to point at the MAP sensor. I betcha it is shot. No way would a good sensor do this. I then read up on what the MAP sensor should be reading with KOEO (key on engine off) and it should be showing ambient. Which this morning it was around 29.5 inHg. Which coincided with the Turbo and the MAF Baro.

28.7 inHg is NOT what it is supposed to be reading KOEO for the MAP sensor!

I'm letting RAM handle this as the MAP sensor is tucked under the turbo outlet piping and the bolts are way back there. Not my job to fix this.

Thanks for everyone's help with this. I'll report back after 8/8.

 

[sag2]

Before doing a hard reset like @Ozymandias mentions, I put it all back together and I decided to grab some data after cleaning the MAF connector and tightening the grounds on the right fender. I see that my Baro and my Turbo closely match:
View attachment 141231

@Ozymandias -- Do you think I should still do a hard reset at this point?

MAP, Baro, and turbo inlet should all read the same KOEO.

 

[Diesel85]

MAP, Baro, and turbo inlet should all read the same KOEO.

@sag2 -- That is what I am believing. The more I dwell on this, it really seems like an ECU issue or a software bug. There is no way this many sensors could be bad. I am itching to find out what RAM is going to do on 8/8 (Thursday).

I really appreciate everyone's help.

Yesterday I had to go on a bit of a trip, 110 miles, and I was getting 30.7 mpg. The CEL went out, but the code was still stored as pending. This time the MAF and Turbo Inlet showed the same (29.9 in/Hg) and the MAP was showing 28.7 in/Hg with KOEO.

More to come.

 

[Diesel85]

I got a call from my dealer, and their diesel tech's wife apparently had a baby. They had to move me to 8/28.

Glad the truck is still drive able.

Quite annoying they only have one diesel tech now with no backup. I couldn't imagine being a hotshotter or a business that had a desperate need to get their diesel truck fixed under warranty. You'd think they would have a contingency plan in place to get a temp tech in, or do some in house training. Obviously they all likely knew well in advance about the situation. It's not like a women suddenly gets pregnant and has a baby.

 

[Tuesdak]

Call some other dealers. It’s not like they gonna be back With A Good Nights Sleep!!!

 

[Diesel85]

Call some other dealers. It’s not like they gonna be back With A Good Nights Sleep!!!

That is a good idea. I'll do that first thing.

This is one thing I like about living where I do... tons of RAM dealers to go to.

Keep you all posted.