Altea limp mode help

[JonTelfer]

Hi all,
I've got an Altea TDi FR which has had some long running intermittent faults. The fault is that it goes in to limp mode when I switch the car on. It never comes on during driving and I can clear the fault by either switching off/on or driving for a few hundred metres and off/on again.

History is:
- First dealer visit reinstalled ECU software
- Second said that the boost sensor had failed and this was replaced
- The fault came back along with a cruise control intermittent fault so it went back into the garage for "deep diagnosis" + new software install.
- Fault came back again and I had a new ECU installed. Cruise control fixed
- Fault came back so it went into the dealers for 5 days where the software was installed x3 times and road tested, no fault found.

- Fault is now back again and cruise control is also bust, so I bought vag-com with a view to getting some more expert help i.e. you guys.

After a reinstall of the ECU I get around 2 weeks of fault free motoring, but then the faults come, and now the fault appears every other time I switch the car on.

This is the autoscan log -

VIN:   Mileage: 28490km/17702miles

00-Steering Angle Sensor -- Status: OK 0000
01-Engine -- Status: Malfunction 0010
03-ABS Brakes -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
56-Radio -- Status: OK 0000
62-Door,Rear Left -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000
77-Telephone -- Status: OK 0000
 
-------------------------------------------------------------------------------
Address 01: Engine       Labels: None
   Part No SW: 03G 906 018 EC    HW: 03G 906 018 EC
   Component: R4 2.0l PPD1.2 G    9583
   Coding: 0050072
   Shop #: WSC 02108

2 Faults Found:
005522 - Altitude Sensor / Boost Pressure Sensor: Implausible Correlation 
               P1592 - 006 - Short to Plus - Intermittent - MIL ON
             Freeze Frame:
                    Fault Status: 10100001
                    Fault Priority: 5
                    Fault Frequency: 22
                    Reset counter: 40
                    Mileage: 28231 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 10:47:27

             Freeze Frame:
                    RPM: 0 /min
                    Torque: 0.0 Nm
                    Speed: 0.0 km/h
                        0.00 %
                    Voltage: 11.87 V
                    Pressure: 1001.1 mbar
                    Pressure: 1469.7 mbar

000257 - Mass Air Flow Sensor (G70): Implausible Signal 
               P0101 - 006 - Short to Plus - Intermittent
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 38
                    Mileage: 28419 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 18:25:04

             Freeze Frame:
                    RPM: 1376 /min
                    Torque: 0.0 Nm
                    Speed: 47.0 km/h
                    Temperature: 30.0�C
                    Pressure: 1299.3 mbar
                    Text:     76    
                    Text: kg/h      

Readiness: N/A

None of the dealers have mentioned the MAF problem that vag com found. Surely their machines would pick this up? Or is it something to do with the way I've scanned the car i.e. engine not running?
The car is under warranty but the dealers can't seem to work out how to fix it. Any suggestions? Also what are the mileage figures for the sensors and why are they different?
My vag-com experience is approximately 15 minutes, but I can pop out and get more logs if needed.

Thanks in advance,

Jon

 

[JonTelfer]

OK - Ross Tech Wiki says:

 18000/P1592/005522 - Altitude Sensor / Boost Pressure Sensor: Implausible Correlation
[edit]
Possible Symptoms

    * Malfunction Indicator Light (MIL) active
    * Limp Mode active 

[edit]
Possible Causes

    * Wiring from/to Boost Pressure Sensor (G31) faulty
    * Ground Spots corroded
    * Boost Pressure Sensor (G31) faulty 

[edit]
Possible Solutions

    * Check Wiring from/to Boost Pressure Sensor (G31)
    * Check Ground Spots for Corrosion
    * Check Boost Pressure Sensor (G31) 

[edit]
Special Notes

    * When found in 2.0l TDI-PPD (BMN), check TSB/TPL's first.
          o Possible Causes: Software Issue, High Resistance in Engine Wiring Harness, Ground Spots corroded
          o Possible Solutions: Check/Update Engine Control Module Software, Check Wiring from/to Boost Pressure Sensor (G31), Check Ground Spots for Corrosion

Anyone know what the "check TSB/TPL's first" means ont he special notes for the 2L TDi?

Thanks,

Jon

 

[Theresias]

TSB = Technical Service Bulletin
TPL = Technical Problem Solution

The additional possible causes/solutions are taken from these.

 

[JonTelfer]

Ah Ok - thanks. Are these made public anywhere?

Jon

 

[Theresias]

Most likely not, only dealers have access to that.

 

[A-Spot]

Dragging up a really old post here, but symptoms match my car, without the replacement eco or software update. Anyone know how this turned out. I’m now looking for loom faults or bad earths!! But not sure how many earths to look for.