TDI Engine: Won't Accept Fuel? Troubleshooting

Hi,

I'm having a problem where the engine is no longer responding to the accelerator pedal.

Regarding career history:
I drove to work in the morning, a distance of about 110 km (and sometimes I drove pretty fast).
(approximately 210 km/h), everything was fine. After work, I started the car and drove off.
At the first traffic light, I stopped after about 500 meters. Everything was normal up to that point.
Then the traffic light turned green, and I wanted to drive off, but there was no response when I pressed the accelerator.
The engine speed slowly increases to approximately 1200 RPM and then gets stuck there, while the glow plug light remains on.
blinking. Car turned off, then turned on => engine runs normally at idle.
Pre-glow lamp off. Then, apply a minimum amount of gas => the engine speed increases until it reaches a certain point.
Over 1000, then the same thing happened as before. The car was turned off, and various things...
Cables in the engine compartment and at the gas pedal were loose; restarted the car.
Everything seems normal, go ahead. After 200 meters, nothing happens. The preheating light is on.
It's blinking again. I fiddled with the cables again => everything is back to normal.
For now, just drive up to 2000 RPM, then later you can also use full throttle, everything is okay.
Arrived home, turned off the engine, and 3 hours later, turned it on again.
Nothing's working again, and this time it's not going to get fixed.
It's like pressing the brake and then wanting to accelerate.
Then nothing will happen.

The error log shows the following:
1. DTCs Found:
18047 - Accelerator Pedal Position Sensor 1/2 (G79/G185): Implausible signal.
35-10 - - - Intermittent

The sensor was replaced by the workshop, but the problem persists.
The car is still at the workshop due to the mobility guarantee.
Mileage: 63,000 km. The car has been chip-tuned.

My questions:
What does the error message 35-10 mean?
I found G185 and G79 in the wiring diagram for an Audi A3.
What else could cause this error code?

Thank you to everyone who read this.

Hi.

G 79 is definitely the standard sensor for the accelerator pedal position.
I'm not familiar with the G 185; it might be a different model.

The increased idle speed is typical of faults in the accelerator pedal sensor. It is intentional and allows the vehicle to limp to a workshop.

Why replacing the part doesn't bring improvement:

Either the replacement part is also broken, or the problem is actually with the wiring harness (a loose connection caused by vibration?), or with the way the motor control unit supplies power to the pedal sensor.

For example, the idle contact must be closed below a certain sensor value, open within a specific range, and remain open above that range.
If only one of these tests fails, the device is considered defective.
Something like that could be caused by a simple (temporary) short circuit in the wire leading to the idle contact. Or by a stray piece of solder in the engine control unit.
Then, of course, 20 new pedal users wouldn't be of any use...

Hi,

The error likely occurred due to a corroded connector on the engine.
control unit. It was the 40-pin connector. The car is running fine now.
normal.

Achim wrote:

The error likely occurred due to a corroded connector on the engine control unit. It was the 40-pin connector. So far, the car is running normally.

Hi Achim,

If a connector is prone to corrosion, this can happen repeatedly... and the next problems are inevitable .

I would like to carefully inspect both sides of the connection (the blade connectors on the engine control unit and the cable connector), check if the elastic plastic seal is missing, and as a precaution, lubricate or oil all the contacts.
Do not use contact spray .

As a precaution, always disconnect and reconnect the engine control unit (ECU) only when the battery is disconnected.

Hi Ulf,

Yes, I did that. The gasket is present, but it has a crack running through it.
roughly half. I ordered a new plug because the seal is...
allegedly not available individually.

Why not use contact cleaner? I've actually been wanting to try Contact 60.
or Contact Laundry, which I believe is Contact WL, and then Contact 61.
Use a corrosion protection product.

BTW, what could I use to verschandeln the control unit after opening it?
Need to be resealed?

Achim wrote:

... Why not use contact cleaner? I've actually been wanting to try Contact 60. or Contact Laundry, which I believe is Contact WL, and then Contact 61. Use a corrosion protection product. ...

This treatment is the only correct one... but it is also the most complex.
Many users only use K60 and then wonder about increased corrosion of the contacts.

Achim wrote:

Why not use contact spray? I actually wanted to use Contact 60 or Contact Wäsche, I think it's called Contact WL, and then Contact 61, which is a corrosion protection agent, to use.

Hi Achim,

Many contact cleaners use chemically aggressive ingredients, which initially provide improvement but then slowly corrode the contact materials.

So, I once managed to fix the rotary switch on a (fortunately inexpensive) multimeter.
Since then, I've been cured of my contact lens intolerance.

Instead, I use spray lubricant (88? also from Kontakt Chemie), saturate the contacts/switches with it, and then actuate them multiple times, or repeatedly connect and disconnect the connection.
The mechanical action breaks up the oxide layer, the oil washes away the dissolved particles, and at the same time forms a protective film against further corrosion.

"I get significantly better results with this product than with contact spray, even in very sensitive applications like noisy switches and potentiometers in hi-fi equipment."

Hello Achim,

Achim wrote:

Yes, I did that. The gasket is present, but it has a crack going all the way through. roughly half. I ordered a new plug because the seal is... allegedly not available individually.

"New grease is certainly the optimal solution. Otherwise, good quality grease also works well; it can even withstand a day in the sun without leaking out of the connector housing."
If I were you, I would have also gotten a new gasket; the connector is too critical. According to Murphy's Law, you'll get stuck in a snowstorm at midnight because of such a connector.

Best regards, Rainer.