Engine No Power, MAF Sensor OK - Troubleshooting

Hello everyone!

A friend of mine is having the following problem:
Da ich jetzt mit meinen Latein am ende bin, er hier nicht posten kann frage ich euch mal. Mein Pseudonym ist dort Niubee: Bitte heflt ihn wenn ihr könnt. He can read, after all!
He is experiencing the following problem:

Engine warm + AC not working. Engine cold, AC works!





Hello NiuBee,

I was just speeding down the highway with the air conditioning on, and I wanted to pull up to the dealership with the engine running.

I only removed the plastic cover and installed my old mass airflow sensor. The car ran at full throttle for 2 hours.

I still went to the friendly mechanic. The error memory indicates:
2 errors.

00553 031
Air mass meter - G70.
Short circuit to ground.
(as you already said)

00575 017
Intake manifold pressure.
Rule difference.

'The friendly employee gave me a solenoid valve for 85 euros and checked if my container was working properly.'

He says that heat can cause expansion, which could lead to the can, the solenoid valve, or the turbocharger getting stuck.

I've also read about the solenoid valve needing to be replaced in other cases, but the symptoms were different...

Can you draw new conclusions from this?



Hello Niubee,

Please post the topic as you suggested in the email to me.

Yesterday, I installed the magnetic valve directly on the motor. There's a second one that my Audi dealer couldn't even find in their system. I sprayed WD40 into my turbo using a tube. I replaced the hose on the vacuum sensor and the fabric hoses in the control unit; that's where the vacuum sensor is located, which detects the control difference.
I oiled the linkage near the turbo; I think it's a bit more responsive now.

Can you tell me which interfaces are worth buying and where they are available at the best prices?

I read a report stating that the engine control unit (ECU) goes into emergency mode not only when there is too much boost pressure, but also when there is too little. I suspect the following possibilities (listed from most to least likely):

1. After 300,000 kilometers, the turbocharger burns out, and the paddles do not adjust as required.
2. Turbocharger worn out, boost pressure too low.
3. The pressure sensor in the control unit is faulty; I'll replace it at the end for 1000 euros.

Unfortunately, it's too cold right now to continue testing. However, I definitely want to log the values using an interface.

My oil level is okay, there's no oil visible, the hoses are full of oil, and even the smallest leak should leave traces.

Best regards, Michael.

Hello,

So...
- What kind of car/engine are we even talking about?
- Lubricating with VTG oil is not a good idea. The oil will carbonize because it cannot withstand the high temperatures. It's better to use copper paste or another heat-resistant lubricant.
- The error code related to the LMM (likely referring to a mass airflow sensor) in the error memory suggests a loose connection or damage caused by rodents chewing on the wires.
- Diagnostic system: http://shop.dieselschrauber.de/product_info.php/cPath/21/products_id/41 or via USB on the laptop.
http://shop.dieselschrauber.de/product_info.php/products_id/45

Best regards, Rainer.

Here's the translation:

'This is about a pre-facelift Audi A4 TDI with 110 horsepower.'

Could it be?

'However, it almost certainly includes a vacuum pressure differential control!'
VTG turbocharger variable geometry adjustment is not working correctly!

This is a request from my friend:

Hello Nuibee.

Can you please send the vehicle data to Rainer at 'Die Dieselschrauber'? He seems very knowledgeable.

Sag ihm, das der LMM im Betrieb abgezogen wurde und deshalb im Speicher steht. Damit wollte ich testen, ob wenn bei mir die Leistung fehlt der Motor wirklich im Notprogram ist. It is like that.
Okay, so right now the old MAF sensor is back in. It definitely wasn't the MAF sensor (just like it wasn't the case for the other 150 people who have installed up to 7 of them). It seems like the MAF sensor is always the culprit when people are out of ideas.

I'm wondering if it's worth disassembling and cleaning the turbocharger.

I'll get myself an interface with software first.

Sure, here's the translation:

'Thanks.'

Take a look at this thread - I had a similar problem.

/viewtopic.php?t=6545&highlight=intake manifold pressure+regulation limit

00553 031
Air mass meter - G70.
Short circuit to ground.
(as you already said)

00575 017
Intake manifold pressure.
Rule difference.


Greetings Michael

Then quickly return that solenoid valve and buy a new mass airflow sensor!

I had the exact same problem. In my case, it was the mass airflow sensor (MAF) that was intermittently shorting to ground. At the moment of the short circuit, it also cut off the power supply to the boost valve, and that's when the limp mode kicked in.

What makes you think it's not the mass airflow sensor (MAF)? Do you get the same error codes even with a new MAF sensor? If so, your next step is to check the wiring to the MAF sensor!

It's probably not the control unit, but that can also be repaired very cheaply. Take a look here: http://www.hitzpaetz.de/


Regards,

Manuel.