Needle Lift Sensor & Air Temp Sensor Issues?

Hello!

I'm having the following problem:
Vehicle: VW T4, engine code AJT, manufactured in 1999, approximately 190,000 km mileage.
Lack of power, rough idle, check engine light on.
Error code: 17655. Needle lift actuator: interruption and/or short circuit after the positive terminal.
17569 Intake air temperature sensor - Open circuit and/or short circuit.
after plus
Errors reappear after being cleared and the system restarts.
Using an oscilloscope, I checked the NHG (negative high voltage) values: at idle, they were occasionally okay (between 4-5 volts), but sporadically jumped to 13-14V. At those moments, the engine also ran roughly and emitted smoke.
The cable connections and grounding connections look very good.
Resistance of the NHG in idle state: 185 Ohms.
Can the NHG be temporarily suspended?
I haven't been able to find what I'm looking for using the search function or by reading relevant articles.
Background:
Radio replacement (from Blaupunkt to Blaupunkt).
Then I added 10-20 liters of fuel.
Error occurred afterwards.
Is it possible that gasoline was accidentally added here?
But wouldn't the engine be knocking terribly?
Do you have any other ideas?

Quote:

Resistance from the NHG in the idle state: 185 Ohms

Defective. Or, in Bavarian: Up the backside.

First of all, thanks for the tip. I'll get back to you when I've planted it.

Best regards, Rocco.

Feedback:

NHG installed, error memory cleared, test drive:

everything is okay. This thing is running smoothly, has power, and no more errors.

It's suspicious when a VW dealer has something like that in stock.

Thank you again!

Okay, have a good trip!

Surely, these errors have nothing to do with the NHG (German Civil Code), right?

Quote:

17569 Intake air temperature sensor - interruption and/or short circuit. after plus

These errors surely have nothing to do with the NHG, right?


Okay, he can't. But apparently, it's not enough for emergency mode, even if 'only' the intake air temperature sensor fails.

But he also writes: No more mistakes .

Perhaps it was just an intermittent error, caused by the sensor being disconnected while troubleshooting or performing other tasks.

Both errors reappeared after clearing the error codes and test driving.
After the NHG (likely referring to a specific part or system) was replaced, the error code related to the intake manifold temperature sensor also disappeared.
for whatever reason.

Hi,

With which device was the error memory read?

Best regards, Rainer.

I use a Gutmann tester, specifically the macs 55, for error analysis.

Excellent device, I highly recommend it to any independent workshop. You can do almost everything diagnostically with it.

@Kosta
I'm not sure what this device can do, but since we're in a VAG-COM world, I can imagine that your post won't go without comments...

Looking at the prices, I think you're better off with VAG-COM, at least when it comes to VAG products.

Hi,

I asked how something was read because, in the past, an error in the reading process could lead to a different error.

Best regards, Rainer.

Hi. Here I am again.
Since he picked up the car, he's probably only driven it in the city, and last weekend he drove it on the highway once, and guess what:
Customer complains about performance issues on the highway at speeds above 120 km/h.
Until then, it won't be noticed.
Unfortunately, the error memory is empty.
The load test (3rd gear, accelerating from 1500-4000 RPM at full load) showed: Target air mass = 850g/h.
The actual yield remained at 600-650g/hour.
New LMM reading: Air mass increases up to approximately 740g/H, but drops below 600 again at around 2500-2700 RPM (during full acceleration). However, the final power output is still lacking.
I will start by working through the article on systematic troubleshooting tomorrow and then get back to you.

Consider also the boost pressure . And then, if there are any further questions, it's best to provide informative logs.

Hi.

Yesterday, I ran several tests and even managed to print out two of them. However, I'm finding it quite cumbersome to upload the logs here.

Results:
The accelerator pedal only goes up to 97%.
Boost pressure at full load: approximately 1550 mbar (target/actual -> equal).
The air mass remains at approximately 600 mg/H (the 740 value he only saw during the initial test drive after the MAF sensor).
(brought about a change)
Brake switch bits toggle simultaneously.
MWB10: The intake manifold pressure and the absolute atmospheric pressure are identical when the engine is stationary.
Cooling system temperature, operating: approximately 85°C.
Fuel injection amount at full load: approximately 30 mg/hour.
Injection start: Desired vs. Actual comparison: OK.
The exhaust system, including the catalytic converter, is approximately 6 months old.
Timing belt (both) replaced approximately 4,000 km ago.
Keyboard control for AGR valve: closed at full throttle, open when releasing the accelerator.
Error memory still empty.

I'm at a loss for the moment.

Best regards, Rocco.