P0101 00 [237] - Implausible Signal

Shanz

Member
Hi All,

I recently had my engine light come on the dash and VCDS returns the following code: P0101 00 [237] - Implausible Signal

I tried cleaning the MAF sensor with Archoil cleaner spray, I reset the code with VCDS but the engine light returned after about 20mins of driving.

So I replaced the MAF sensor, cleared the codes with VCDS and again the engine light returned after about 20mins of driving.

So it seems that the MAF sensor isn't the problem.

I have no other error codes displayed with VCDS so not sure what to check.
The intercooler looks ok, no hissing or anything but I can't really tell.

What is the best way to check for leaks in the intercooler or air intake?

Cheers for any advice.
 
Last edited:
Please share VCDS Auto-Scan?
Hi, this is the original fault scan (from the orignal MAF).
Please see below:


--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 7H (7E0)
Scan: 01 03 04 08 09 10 15 17 19 25 5F 61 0B


01-Engine -- Status: Malfunction 0010
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
10-Park/Steer Assist -- Status: OK 0000
15-Airbags -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
5F-Information Electr. -- Status: Malfunction 0010
61-Battery Regul. -- Status: OK 0000

-------------------------------------------------------------------------------
Address 01: Engine (J623-CAAB) Labels: 03L-906-022-CAA.clb
Part No SW: 03L 906 019 GE HW: 03L 907 309 L
Component: R4 2,0L EDC X38 6292
Revision: 22X38--- Serial number: 00000000000000
Coding: 01114012232401080000
Shop #: WSC 26214 051 00000
ASAM Dataset: EV_ECM20TDI01103L906019GE 003004
ROD: EV_ECM20TDI01103L906019GD.rod
VCID: 74E7B6B6DF7A05E2B4-8020

1 Fault Found:
4795 - Mass Air Flow Sensor (G70)
P0101 00 [237] - Implausible Signal
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 153534 km
Date: 2025.09.03
Time: 07:37:08

Engine speed: 1596.00 /min
Normed load value: 0.0 %
Vehicle speed: 69 km/h
Coolant temperature: 90 °C
Intake air temperature: 25 °C
Ambient air pressure: 980 mbar
Voltage terminal 30: 14.680 V
Unlearning counter according OBD: 40
Air mass: actual value (mg/stroke): 674.7 mg/stroke
Standardized airflow ratio: filtered: 0.8336
EGR solenoid valve: actual value: 99.54 %
Throttle valve adapter: actual value: 99.66 %
Charge air pressure specified value: 1060 hPa
Charge air pressure: actual value: 1178.2 hPa
Mean injection quantity: 0.00 mg/stroke

Readiness: 1 1 0 0 0

-------------------------------------------------------------------------------
 
The prime suspect is the intercooler. Any oil stains at the bottom?

Pictures

Next step would be - blockmap files from engine - to see any discrepancies in e.g. charge pressure data
1) Engine blockmap - Ignition ON/engine OFF
2) Engine blockmap - Engine running at idle


How-to create a blockmap file:

[VCDS]
[Applications]
[Controller Channel Map]
- Single Controller Address = 01
- Login or security access code: Leave blank
- Function: Measuring values
- Output: CSV file
[Go]

The result CSV files are saved into dircetory C:\Ross-Tech\VCDS\Logs
Please attach the files here.

Note: only VCDS HEX-V2 and HEX-NET -cables have this capability
 
The prine suspect is the intercooler. Any oil stains at the bottom?

Pictures

Next step would be - blockmap files from engine - to see any discrepancies in e.g. charge pressure data
1) Engine blockmap - Ignition ON/engine OFF
2) Engine blockmap - Engine running at idle


How-to create a blockmap file:

[VCDS]
[Applications]
[Controller Channel Map]
- Single Controller Address = 01
- Login or security access code: Leave blank
- Function: Measuring values
- Output: CSV file
[Go]

The result CSV files are saved into dircetory C:\Ross-Tech\VCDS\Logs
Please attach the files here.

Note: only VCDS HEX-V2 and HEX-NET -cables have this capability
Hi,

I tried to create the blockmap .csv files as per your instructions. CVDS tries to do something, it launches a new window, communicates ok and then closes but no .csv files are created in the VCDS/logs folder.
So I'm assuming my cable is not HEX-V2 and HEX-NET.

I had a look at the intercooler and there is a damp looking patch around the bottom right hand side. There's not loads of oil, but it is damp looking.

Thanks for you help with this.
 
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I tried to create the blockmap .csv files as per your instructions. CVDS tries to do something, it launches a new window, communicates ok and then closes but no .csv files are created in the VCDS/logs folder.
So I'm assuming my cable is not HEX-V2 and HEX-NET.
Quite likely. The "HEX..." would be on the label clearly.
 
there is some damp though.
That's certainly suspicious. The amount of oil in the air intake piping is very small thus not much to be seen.
There doesnt appear to be any whooshing sound coming from the intercooler.
I guess you mean at standstill? There is hardly any boost pressure without engine load so not easy to hear. Revving engine doesn't change it.
 
Define damp?
The bottom right part of the intercooler grill and rail has a wet surface. It's not dripping, but does look like oil.
In contrast to the rest of it, which is completely dry.
 
Last edited:
Degrease it, let it dry and be sure it’s clean. Take it for a hour long drive under load and check again for oil patches.
If you run a smoke test ref post #2 it should spot a leak, otherwise remove the intercooler and fill with water and see if it leaks. Degrease internally first.
 
I had the same issue earlier this year and it was the intercooler. The straps had rotted away and it was damp with oil at the bottom. Pretty easy fix. Bumper off and you can access the intercooler.

IMG_7839.webp

IMG_7847.webp

IMG_7852.webp
 
It was 9 years old and 88k. It was just the steel straps that rotted away and then the core eventually separated at the bottom.
 
I had the same issue earlier this year and it was the intercooler. The straps had rotted away and it was damp with oil at the bottom. Pretty easy fix. Bumper off and you can access the intercooler.
My 2016 did this too a couple of years ago. The straps rusted away and detached allowing the soft intercooler core to inflate under boost, eventually cracking a seam.
 
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