LMM: What is it? See pictures!

Hello,

Has anyone ever seen an LLM like that before?

Is this any good? Or is it a cheap Chinese knock-off? It looks like a diode trick.

It looks normal, except for the slightly sloppy finish.
That part hanging in the measurement channel is an NTC thermistor. Not many people have them, but they do exist.

TDI-GTI-4-Motion wrote:

The part that's hanging in the measurement channel is an NTC.

Not many people have those, but they exist. } Hmm, that cylindrical red part with the long connecting wires looks very much like a diode. The NTCs I've seen so far, without any special housing shapes (e.g., a mounting flange for the housing), are more disc-shaped.
Therefore, I suspect that the LMM (lambda sensor) might be modified, perhaps for tuning purposes, or that an old or defective part has been "reanimated" using a diode to mask the problem.


@ flightmaster:
If you have a soldering iron and a multimeter, desolder one of the wires from the red part and measure its resistance in both directions. An NTC resistor will always provide the same value (except for the cooling effect after desoldering), while a diode will show significantly different readings.

ulf wrote:

Hmm, that cylindrical red part with the long connecting wires looks very much like a diode to me.

It might be one, but there are also some that have those features, and others that don't.
I've already held original, Bosch-packaged items in my hand that looked exactly the same.

What exactly is a picture supposed to convey?

Hi,
Looking at the connection points for the "?Diode" and the slot in the housing for the wire, it's clear that the housing is definitely designed to accommodate that part. In my opinion, it's therefore a standard production model. Is there anything printed on it, or is there a colored ring?
hg
Herbert.

This is an additional temperature sensor:
http://rb-aa.bosch.com/boaasocs/index.jsp;jsessionid=85D92630D66DE1E053C6DB8D276425D4?ccat_id=72&prod_id=340

fantomas wrote:

This is an additional temperature sensor: http://rb-aa.bosch.com/boaasocs/index.jsp;jsessionid=85D92630D66DE1E053C6DB8D276425D4?ccat_id=72&prod_id=340

OK, according to the diagram in the lower right corner, the number 8 in the diode package is actually a temperature sensor .

Do V6 TDI engines usually have this issue? Or are the mass airflow sensors (MAF sensors) from Hitachi?

"Bosch also also offers an external diode. This diode is a standard 1N4148. I once retrofitted one and made a VW mass airflow sensor (Bosch) compatible with a BMW (also Bosch). BMW wanted to charge over 300 euros for a mass airflow sensor."

Best regards.
Christian.

chris11 wrote:

There are also external diodes available from Bosch. The diode is a standard 1N4148.

That's what the part looks like in the photos. However, a 1N4148 is definitely not an NTC, even though it exhibits an NTC-like change in forward voltage.
What, then, is the function of the diode in the OEM wiring of the mass airflow sensor (MAF)?

Hi,
The documents from Fantomas were, after all, quite clear?
hg
Herbert.

It is definitely a thermistor, for example, an NTC M87.

fantomas wrote:

It is definitely a thermistor, for example, an NTC M87.

Ah, that solves the (my) riddle -> thank you

No no.

I'm not concerned about the possible diode that might be on top of it.

but to place this component in the center of the thermal sensor. Possibly a thermistor.

The HF looks fake, at least the workmanship is pretty bad.

This LMM also weighs 5g less than the original and has no markings on the back.

Sure, here is the translation of the text from German to English:

'MFG' is an abbreviation for 'mit freundlichen Grüßen,' which means 'best regards' or 'sincerely.' It is commonly used in German-language emails and letters.

flightmaster wrote:

This LMM also weighs 5g less than the original.

So, it's definitely a part for racing use.