SLC Free temp reading potential error

SLC Free 2
1

Hello all,

Reading the temperature from the LCD on the SLC Free v2 shows it seems to always start at 765C, is this a fault? Or is this normal?

The sensor is in free air, and has not been installed in any exhaust system yet.

Occasionally the temp reading will flicker between 765 and 815C, not sure if anyone has seen similar before.

I checked the datasheet for the LSU4.9 and didn’t see anything about the sensor having a thermistor or anything else in it, so perhaps the reading on the LCD is the target temperature?

Any tips would be appreciated!

Thank you,
Rog

2

The lowest temperature that can be displayed is 765C so any temperature less than 765C will show as 765C.

I think there is a miswiring with your 6 pin sensor cable, or you are using a clone LSU 4.9 sensor.

3

Understood! Thank you,

How does the LSU 4.9 send the temperature back to the controller?

I am using the sensor that came with the SLC Free, but I am not sure it is genuine as it has Spartan laser engraved on it?

I will double check the wiring, however I am fairly certain it was correct.

I haven’t tried the electronics ground separate from the heater ground? Could that be a part of the problem?

Thanks again for the replies!
Rog

4

If you purchased the sensor from me then it is a genuine bosch sensor.

The ground is not the issue. It is most likely the cable.

The resistance of the sensor nernst cell is measured by the controller, from the resistance the sensor temperature is determined.

5

Ok! I had no idea you were the person behind all this, thanks very much for taking the time to reply to messages like mine haha!

I haven’t been back to the vehicle yet, but I did get some photos of the cable sent through to me, I’ll triple check and go from there!

Thanks again for the product, and the service!
Rog

6

Ok, thank you in advance for your patience,

I have checked the connections on the plugs for the sensor and for the controller, I found the yellow and the white mismatched :person_facepalming:

I have also installed the sensor in the exhaust manifold, and it appears to show a very consistent LAM: 1

Would the sensor or the controller be more likely to suffer damage at the transposed connection? What is the best method to isolate the two and confirm?

Thank you,
ROG

7

@toalan, what would the most likely damage be from the reversed harness?

I cannot seem to find a schematic for the board to try and diagnose the fault, only the Gerber files etc, would you have the schematic released somewhere?

Appreciate any further assistance!
Rog

8

This is the schematic

In the user manual, the contacts with the white circle carries 12v. If the 12v wire is miswired then likely your sensor is destroyed and also the controller.

9

Bummer! Cheers for the heads-up! Guess I better get another one then…

Do you have a distributor in Australia/Pacific? The shipping costs more than the controller to Aus…

Cheers!

10

For SLC Free 2, I have no distributors.