02 ALH Limp Mode only in Winter Temps.

Hi All
I have a 2002 Jetta TDI 5spd, and been suffering thru a Intermittent "Limp Mode" that occurs only in the Winter when the Temperature gets to like Below 20 Deg. ?

I have owned this car for 11 Years now and Spring/ Summer and Fall - No Issues.

So in CT this week, we had 37 Deg. this Morning - No Issues.

Monday, 19 Deg. - Limp Mode after about 5 Minutes on the Highway, Warmed up about Half way on the Temp Gauge.

When I get this Limp Mode, If I throw the Clutch in, Turn the Ignition off and Right back on and let the clutch up, Car Starts and No Limp Mode, So I don't feel this is a Turbo Issue.
More of a System Control Issue or something from the ECU ?

Thanks
Timmy

Codes?

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Hello Ed
I will Scan Tonight, I want to say No ???
And I forgot to mention, I did the Intake Cleaning a Few Years ago, Cleaned the EGR, Did the "Oven Cleaner/ Turbo Vane Cleaning" like Twice last year, Replaced the MAF Sensor, N75 Valve (Waist Gate), N18 (EGR Control) valves.

I would try running without the MAF sensor plugged in and check the coolant and fuel temperatures when cold to make sure they match ambiant and they rise to operating temperatures properly.

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Also, if it's going into limp mode, make it go into limp mode then try scanning the codes. Sometimes the codes won't be permanent unless it happens enough times.

The ECU can go into limp mode for several reasons, usually to protect the engine from possible damage due to what data it "sees" from the various sensors. Typically over/under boost situations and the related vacuum leak(s) and/or turbo issues. MAF failure also and cold air is "heavier/denser" than warmer air, so maybe it goes out when a line is crossed there perhaps. As mentioned, either unplug it and "test" drive or compare the actual vs requested values to see if they almost match.
Other thing may be injection timing, as it advances in colder temps. So, perhaps, if your timing is already very advanced, when the temp drops and more advance is supplied it goes too far, then goes into limp. Probably not, but easy to check.

french69ssrs said:

I will Scan Tonight, I want to say No ???
And I forgot to mention, I did the Intake Cleaning a Few Years ago, Cleaned the

Click to expand...

You have to scan when you get limp mode.
The code clears when you shut the car off.

If it's only in freezing weather I would think possibly moisture in the vacuum system somewhere.
Engine heat should melt it but maybe to much cold air flowing through.

french69ssrs said:

Hello Ed
I will Scan Tonight, I want to say No ???
And I forgot to mention, I did the Intake Cleaning a Few Years ago, Cleaned the EGR, Did the "Oven Cleaner/ Turbo Vane Cleaning" like Twice last year, Replaced the MAF Sensor, N75 Valve (Waist Gate), N18 (EGR Control) valves.

Click to expand...

Why would you even have to do this over and over? If the turbo vanes are coking up then you are not driving the engine hard enough.

I destroyed a higher mileage vnt15 with this "cleaning".

It's best to drive these diesels hard for a bit in the summer. More so in the winter. If you can't push your vnt turbo vane actuator with 1 finger the ~3/4" travel, it's likely the vanes are getting gummed up and the computer is sensing that requested vs actual boost has a deviation, and enters limp mode.

It's a pain for sure. Dont idle these engines in the winter with egr still active. Drive em to warm up and block a portion of the radiator if you're not getting to operating temp.

A while after I retired I was starting to get limp mode running around in the city.
I went for a 15 mile ride down the highway in 4th gear with the tach at about 3K or so.
Turned around & same going back.
It did seem to clear the problem.
Costs a gallon of fuel if you want to try it.