please help!!! Intermittent limp mode in low rev range

[MP25278]

Hi all,
I'm hoping that some kind VAG genius out there will be able to put an end to the 3 years of pain and confusion I've suffered with my Mk5 golf GT TDI 170 (DPF removed and mapped out)... I apologise in advance for the long post but I think the details are relevant...

So, im having these fault codes:

Address 01: Engine Labels: 03G-906-018-BMN.clb
Part No SW: 03G 906 018 DF HW: 03G 906 018 DF
Component: R4 2.0l PPD1.2 0229
Revision: --H22--- Serial number: VWZ7Z0F8031527
Coding: 0000072
Shop #: WSC 00191 264 15243
VCID: 6CD7223B4F7E2C7E58B-8039


3 Faults Found:
000257 - Mass Air Flow Sensor (G70)
P0101 - 006 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00000001
Fault Priority: 1
Fault Frequency: 11
Reset counter: 30
Mileage: 184182 km
Time Indication: 0
Date: 2000.00.00
Time: 19:25:34


Freeze Frame:
RPM: 1856 /min
Torque: 0.0 Nm
Speed: 45.0 km/h
Temperature: 29.0°C
Pressure: 1171.5 mbar
Text: 164 kg/h
(no units): 0.70


008825 - Leak in Air Intake System
P2279 - 006 - - Intermittent
Freeze Frame:
Fault Status: 00000001
Fault Priority: 5
Fault Frequency: 22
Reset counter: 40
Mileage: 184202 km
Time Indication: 0
Date: 2000.00.00
Time: 13:20:55


Freeze Frame:
RPM: 1440 /min
Torque: 80.0 Nm
Speed: 30.0 km/h
Pressure: 1746.6 mbar
Pressure: 1789.2 mbar
(no units): 0.67
Text: Kein Messwert verfuegbar


000258 - Mass Air Flow Sensor (G70)
P0102 - 007 - Signal too Low - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10100010
Fault Priority: 5
Fault Frequency: 14
Reset counter: 40
Mileage: 184203 km
Time Indication: 0
Date: 2000.00.00
Time: 16:42:18


Freeze Frame:
RPM: 0 /min
Torque: 0.0 Nm
Speed: 0.0 km/h
0.00 %
Voltage: 12.43 V
Mass Air / Rev.: 872.0 mg/str
Mass Air / Rev.: 0.0 mg/str

The strange thing is that the so called "cage mod" which basically involves putting dielectric grease on the female connector of the maf, had actually solved this problem and I had no issues for well over 6 months. I thought the problem was fixed but then a few weeks back, the dreaded check engine light and coil light came on and went straight into limp - no revs above 3000 and loss of boost. This seems to only occur when the engine is in the low rev range and usually as I've just changed into 3rd although it happened in 2nd a few times too. Now, I'm not what you'd call a conservative driver so the car does get a good thrashing (within legal limits of course!) but if the limp mode comes on, I can actually very quickly switch off the ignition and back on again and the limp disappears and all power is restored. The other thing is that if I unplug the maf, the power is still the same yet it never goes into limp. As I've had my dpf removed theres not really an issue with driving like this other than the esp doesnt work (this makes the wife worry so as you can imaging i need to get this sorted!)




heres some other readouts:


12:13:04 Group 001: Injection Quantity
850 /min Engine Speed (G28)
7.0 mg/str Injection Quantity
4.1°KW Injection Duration (specified)
27.0°C Coolant Temperature (G62)


12:13:04 Group 002: Idle Speed
848 /min Engine Speed (G28)
0.0 % Accel. Pedal Pos. Sensor 1 (G79)
00001000 Operation Status
27.0°C Coolant Temperature (G62)


12:13:04 Group 010: Charge Pressure Control
540.1 mg/str Mass Air Flow (actual)
1026.5 mbar Atmospheric Pressure
1022.7 mbar Boost Pressure (actual)
0.0 % Accel. Pedal Pos. Sensor 1 (G79)

Any suggestions on what might be going on here would be greatly appreciated!!!

[Crasher]

As the DPF has been removed I will not get involved.

[MP25278]

Hi Crasher,

Thanks for your reply. The DPF was removed purely due to an ECU error. I would rather have not had it removed to be honest - it would have saved me £700!!! The map was purely to map out the dpf.. no performance map or economy. The issue im having though is nothing to do with the DPF. To me, the problem seems to be a connection issue as mentioned, when the maf is unplugged, i get no limp mode issues at all.

Thanks again for your response though.

[Ste1981]

Is it a genuine maf

[Crasher]

Have the DPF refitted and the car reflashed with the latest map and go from there. Recently I spent nearly a year chasing a viscous under load hard load high rpm misfire on a customers highly modified Golf 5 and two rolling road sessions at different “specialists” failed to identify it. I wanted to install the OE map a long time ago but it was not on the ODIS server so I could not. Then I noticed almost by accident it was on the APR server so I asked nicely and they let me install the OE map. It ran like a bag of **** because the fuelling on the bigger injectors was too rich but with the piggy back controller I had installed I was able to dial them in and get it running smoothly. It was then that I noticed each time the misfire occurred it threw up a crank speed sensor signal code, it turned out the original remap had a silly exhaust bark overrun feature but this caused the engine light to come on with a G28 error so they removed the ECU’s ability to recognise a crank speed sensor signal error. My thoughts on their work would generate a lot of *******************

[philipharmes]

I noticed with all your readouts that the coolant temperature is always showing in the 20'sC which isn't correct, unless you had just started it.

Also all the MAF faults are " INTERMITTENT ", I would check out all the wires around the plug for breaks & check them for continuity back to the ECU, while giving the loom a bit of a stress test.

[MP25278]

Hi Ste1981,
Sorry for the delay in responding... yes the maf is OEM. Tbh I only ever use original stuff. Its really frustration as the car runs perfectly other than this issue. The maf is still fairly new and has been cleaned recently - in case of any dirt buildup. The reason that it seems to go into limp is because the ecu is getting an unusual reading - hence it throws it into limp. As mentioned before though, if i quickly switch off then on again.. the limp clears and full power is restored... with no maf plugged in, the ecu relies on the MAP and this rectifies the issue.

If anyone has experienced this problem.. please please let me know how you fixed it... the cage mod worked great for about 6 months .. no limp at all.. now im stuck as its MOT time in a few months and I really dont want to have to get rid of it just because of what seems like a fairly simple issue!

[MP25278]

Hi philipharmes,

Yes, I completely agree.. this is the train of thought I have been going down for some time due to the intermittent nature of the issues... do you think theres a possibility of a connection loose at the ecu itself?

[MP25278]

sorry forgot to mention coolant query - yes, had only just started the engine

[Crasher]

You say the Air Mass Meter is OEM, but is it genuine VW from a main dealer or TPS.