NMS P026A and P0111 Code Diagnosis

[jw4free]

2012 Passat TDI SE

Summary: Engine CEL, Ran Ross VCDS scan, discovered code P026A and P0111. Cleared. Did research. Ordered MAP sensor (G31). Engine CEL again. Ran Ross VCDS scan. Got same Codes. Cleared codes. Pulled sensor. Discovered greenish oil/water condensation froth. Cleaned sensor, and replaced. Engine CEL again. Cleaned upper intercooler area with rag (limited success). Replaced sensor. Success.

Note Sensor G31 and G42 are a combined Bosch MAP and IAT sensor.

Sunday,12,February,2017,14:15:03:12876
(Scan truncated)
12642 - Charge Air Cooler
P026A 00 [237] - Efficiency Below Threshold
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 9
Mileage: 151073 km
Date: 2017.01.30 (Tuesday evening)
Time: 17:06:40

Engine speed: 2142.50 /min
Normed load value: 59.6 %
Vehicle speed: 113 km/h
Coolant temperature: 84 °C
Intake air temperature: 44 °C
Ambient air pressure: 980 mbar
Air mass at air mass meter 1: 118.2 kg/h
Temp sensor for low-pressure EGR after cooler: raw value: 103.3 °C
Outside air temperature: 16.5 °C
Intake air temperature before throttle valve: calculated: 25.3 K
Calculated temperature of compressor wall: 76.7 °C

5552 - Intake Air Temp. Sensor (G42)
P0111 00 [232] - Implausible Signal
MIL ON - Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 3
Mileage: 151398 km
Date: 2017.02.02 (Thursday Morning)
Time: 06:43:17

Engine speed: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 3 °C
Intake air temperature: 37 °C
Ambient air pressure: 1000 mbar
Temp sensor for low-pressure EGR after cooler: raw value: -0.9 °C
Action:
Ran Ross VCDS scan
Ordered new MAP sensor after google, TDIClub forum searches

Saturday,18,February,2017,11:21:46:12876
(Scan truncated)
12642 - Charge Air Cooler
P026A 00 [237] - Efficiency Below Threshold
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 152434 km
Date: 2017.02.13 (Monday mid day)
Time: 11:29:13

Engine speed: 1586.50 /min
Normed load value: 0.0 %
Vehicle speed: 85 km/h
Coolant temperature: 86 °C
Intake air temperature: 49 °C
Ambient air pressure: 990 mbar
Air mass at air mass meter 1: 117.0 kg/h
Temp sensor for low-pressure EGR after cooler: raw value: 78.8 °C
Outside air temperature: 7.0 °C
Intake air temperature before throttle valve: calculated: 25.5 K
Calculated temperature of compressor wall: 66.7 °C

5552 - Intake Air Temp. Sensor (G42)
P0111 00 [237] - Implausible Signal
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 152407 km
Date: 2017.02.13 (Monday Morning)
Time: 06:45:46

Engine speed: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 1 °C
Intake air temperature: 45 °C
Ambient air pressure: 990 mbar
Temp sensor for low-pressure EGR after cooler: raw value: 1.2 °C

Action:
Wiped off sensor, sprayed down with Sea Foam and compressed air. Lubricated o-ring with dielectric grease, and re installed.

 

[jw4free]

Feb 25th

Saturday,25,February,2017,15:52:51:12876
(Scan truncated)
12642 - Charge Air Cooler
P026A 00 [237] - Efficiency Below Threshold
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 153213 km
Date: 2017.02.19
Time: 11:21:21

Engine speed: 1945.00 /min
Normed load value: 52.2 %
Vehicle speed: 102 km/h
Coolant temperature: 97 °C
Intake air temperature: 66 °C
Ambient air pressure: 980 mbar
Air mass at air mass meter 1: 119.1 kg/h
Temp sensor for low-pressure EGR after cooler: raw value: 92.0 °C
Outside air temperature: 19.0 °C
Intake air temperature before throttle valve: calculated: 24.0 K
Calculated temperature of compressor wall: 74.9 °C

5552 - Intake Air Temp. Sensor (G42)
P0111 00 [237] - Implausible Signal
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 153189 km
Date: 2017.02.19
Time: 10:01:01

Engine speed: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 12 °C
Intake air temperature: 63 °C
Ambient air pressure: 980 mbar
Temp sensor for low-pressure EGR after cooler: raw value: 13.3 °C

Actions:
Ran Ross VCDS Scan
Cleared Codes
Pulled 03G 906 051E
Note: Greenish oil/water froth (less than previous, but still apparent)

Voltage check: 0 281 002 9770 281 002 976
OldNew
1-4 1.54 kOhm1.61kOhm
1-3 3.14 kOhm3.26 kOhm
1-2 0.46 kOhm 2.95 kOhm
2-3 3.60 kOhm6.17 kOhm
2-4 2.01 kOhm4.44 kOhm
3-4 1.59 kOhm1.65 kOhm

Speculation: oil/water condensation froth creeps into the sensor and decreases resistance, and causes IAT Portion of sensor to read “Implausible Signal”. This in turn causes the P026A code as the computer suspects the intercooler is compromised.

Note: 03G 906 051E = 0 281 002 977 = 0 281 002 976
Absolute pressure sensor 50-XXX kPa with integrated air temperature sensor. Supply voltage 5V. Bosch compact connector. Pin =1 Ground, Pin 2 =NTC (Temp), Pin 3 =+5 V, Pin 4 =Output signal. Vacuum connection: O-ring

Replaced with New sensor 0 281 002 976 (bought thru e-bay: less than $50)

So Far So Good.

 

[VeeDubTDI]

Good post! Thanks.

 

[740GLE]

Sorry to necro bump this thread but, I'm going to remember this if we ever get those codes. .

How many miles on the car and whats the driving style? looks very similar to the goop found in my IC hoses on my old 2010. Pics taken at 10K oil change wayyyyy back in 2010.

 

[jw4free]

I'm at 126K miles.

I drive in the slow lane, and try not to accelerate up hills. Wannabe hypermiler, so I guess my driving style would contribute to this gunk buildup.

Side Note:
I have a picture of my odometer at 123456 789.0, but I can't seem to upload it to the pics.

 

[RuneTDI]

i am now getting the PO26A code in my 2013 passat w 79k miles. can someone translate this thread for me please in simple terms. just replace the sensor or do i have to clean any part of the intercooler? thanks, rune

 

[Tom in PT]

I had P026A code a year ago, dealer replaced sensor, now code is back ~ 5,000 miles later. I'll try removing it and cleaning it and clearing code and see what happens.

Am I driving with too light a foot to keep this from gumming up?

 

[Tom in PT]

Well, I pulled the sensor (Torx T30 for fasteners) and it looked like Post 1 photo, cleaned with a can of spray MAF sensor cleaner I had in the garage, reinstalled and cleared codes. Will report back after a week of driving.

 

[flyboybob]

tom,

pm sent.

bob.

 

[740GLE]

I wonder if disconnecting and cleaning/quick wipe IC piping to the W2A IC is needed similar to draining the goop of the Gen1 IC.

 

[Tom in PT]

After cleaning the sensor, clearing codes, and driving about 100 miles the CEL has not returned and all is normal. If I can get the lower intercooler hose off and clean the lower end of the intecooler that may delay the fouling of the sensor. But, in any case, I think I will make it a habit of cleaning this sensor every oil change. It only takes a few minutes tops. Keeping the lower intercooler area and adjacent piping clean can't hurt.

 

[jw4free]

Decided to do an inspection at this oil change:

MAPT Sensor at 135,000 miles. Looks Good.



Bottom connection at intercooler opened for inspection. Collected a few drips of oil.



Sample of oil and condensation / moisture in bottom intercooler.



I swabbed out the bottom of the intercooler with a rag, blew out the intercooler from MAPT Sensor connection, and reinstalled the elbow.

Typical buildup? or should I be expecting to utilize my VAG warranty for turbo replacement in the next 2 years?

 

[740GLE]

That looks like mostly oil, any amount of water will turn it milky and real nasty looking (chocolate milkish), this was from my CJAA with plauged IC icing (before new IC was installed).



I'd say what you're seeing here is normal and a good routine to wipe clean that IC elbow every other or every 3rd oil change.

 

[dgboswell]

Where can I get a reliable sensor as discussed? I ordered one previously on Amazon, received, installed and got another issue form it. Cleaned old sensor and installed. Fine for 50 miles and CEL came back on. Bad sensor? Actual VW part number?

 

[Tom in PT]

Part number is Bosch 0281 002 976. I bought mine from a seller in Europe, legit seller of VW OEM parts. Buy from a reliable source, dealer, etc., not an ebay knockoff.

 

[dgboswell]

Craziness going on with my 2013 Passat TDI. Got the 1500 mile warning ding, then before the short trip was over to pick up two boxes of DEF, got the dreaded 200 mile warning. Filled her up at home, warning light with tool still illuminated, and now car won't start at all. Tried waiting 30 seconds with key on. Pulled negative battery cable, performed system reset. NOTHING

 

[Tom in PT]

Investigate the status of the dieselgate warranty for your car,

 

[dgboswell]

Just did. Car's at dealer. $1300 to fix def tank. Out od warranty by 30000 miles. Still cheaper than two car payments

 

[thesteed46]

My CEL came on for a P0111 only. Checked the sensor and it was covered in the same green goo. Cleaned it off and the light came back on after a day. I ordered a new sensor and went to put it on and the sensor was covered worse than before. I am hesitant now to replace the sensor before I am able to get the intercooler tubes cleaned out as I don't want to ruin a good sensor. I guess my question is: Is the P026A code inevitable? Is the intercooler replacement covered under the dieselgate warranty, if it needs it?

 

[Tom in PT]

P026A code is probably in your future - intercooler is too inefficient with all the buildup. Clean intercooler out with diesel fuel poured into the sensor hole at the top, plug lower end of interooler with a rubber stopper, let sit, drain, repeat. (Flyboybob has a thread on this topic) Intercooler replacement is covered under the dieselgate warranty. That warranty might be expired depending on when you did the fix, read the warranty booklet.

 

[thesteed46]

P026A code is probably in your future - intercooler is too inefficient with all the buildup. Clean intercooler out with diesel fuel poured into the sensor hole at the top, plug lower end of interooler with a rubber stopper, let sit, drain, repeat. (Flyboybob has a thread on this topic) Intercooler replacement is covered under the dieselgate warranty. That warranty might be expired depending on when you did the fix, read the warranty booklet.

Thank you, I appreciate the information. I believe I have about 12,000 miles or 4 month left.

 

[thesteed46]

P026A did end up coming on by Friday last week. Called and got it scheduled at the local VW Dealership to get it checked out and I am getting the runaround. They are claiming the IAT/MAP sensor is bad(which I don't doubt that it is) and that is causing both the P0111 and P026A codes. I told them the intercooler is going to need replaced and they said they have to have a static fault code for it, which I thought P026A would be sufficient. I've told the service advisor that the sensor will be bad in a week, and asked what will happen then. Also asked why the sensor was bad and awaiting a reply on that. I've heard all the horror stories about getting stuff covered under the warranty. I was hoping this would be simple, guess I was wrong.

 

[danmin]

rent a VCDS tool and scan it with that. $35 for a week rental

 

[Tom in PT]

I'd push back against the dealer to fix it and keep fixing it until the warranty is up. Bring the booklet with you, read it with them, and stand firm.

 

[thesteed46]

I tried everything I could. I even spoke with the service manager. I guess the P026A code is not the correct code to get the intercooler replaced under warranty. He confirmed the sensor cause both codes. They replaced it and light did not come back on the test drive. He did tell me that they want to replace the intercooler but just can't do it without the right code. He said getting it in now and when it most certainly come back on in the future will help them to have a case with warranty for a leaking intercooler that should help get it covered if the specific fault code does not come back on. I'll get it back today, so we'll see how long it takes for this sensor to go bad.

 

[740GLE]

have you called VWoA?

 

[thesteed46]

have you called VWoA?

I've not had the time. I did do a quick "chat" with them online and they were no help and essentially said we cant help you and if you are not satisfied with your dealer, we can find another one in your area. CEL has stayed off so far this week.