LED code reader/ECC help

Peevarino · Post by **Peevarino** » 04 May 2019, 07:30

Built a little code reader for sorting out my no heat issue, but the LED just stays on, no blinks when switched on.

It’s a 12v, and there’s a resistor, when my switch is turned off it’s off when plugged into the correct spots on the OBD output.

Ideas? Needs a different resistor?

I don’t need the heater yet, but it’s humid in Louisiana, and it would be nice to have defrost in the morning

Post by **jreed** » 05 May 2019, 06:00

Sorry to hear you're having trouble getting the codes to read. What is the resistance value of resistor you're using? Which pins are you plugging the code reader into?
I got good results with the circuit shown below, plugging the switch between pins 5 (GND) and 6 (ECC) and the positive side of the LED into pin 16 (+12V). I used a 5K Ohm resistor in line with the LED to prevent overcurrent thru the LED.
viewtopic.php?f=1&t=50443&start=13

Post by **RickHaleParker** » 05 May 2019, 06:24

The led flash code readers are for Fenix 5.2, Bosch LH 3.2 Jetronic & Motronic 4.3.
They don't work on Motronic 4.4 or Motronic 7.0.
Your 2009 has Motronic 7.0.

Peevarino · Post by **Peevarino** » 05 May 2019, 08:06

jreed wrote: ↑05 May 2019, 06:00 Sorry to hear you're having trouble getting the codes to read. What is the resistance value of resistor you're using? Which pins are you plugging the code reader into?
I got good results with the circuit shown below, plugging the switch between pins 5 (GND) and 6 (ECC) and the positive side of the LED into pin 16 (+12V). I used a 5K Ohm resistor in line with the LED to prevent overcurrent thru the LED.
viewtopic.php?f=1&t=50443&start=13

Unsure, it’s got heat shrink over it, but I’m pretty sure that’s the issue. It’s a 12v rated led, assumed (poorly) it would work fine.

Those are exactly the pins I was using.

I posted in here because it’s for a 97 850, not the 09 I have listed in my profile.

Post by **RickHaleParker** » 05 May 2019, 16:41

Peevarino wrote: ↑05 May 2019, 08:06 I posted in here because it’s for a 97 850, not the 09 I have listed in my profile.

Motronic 4.4 started showing up in some '96 850s.
"97 is pretty much the year they moved to Motronic 4.4.

Peevarino · Post by **Peevarino** » 05 May 2019, 17:51

Really? I had read multiple places that the R was still 4.3 in 97. It made no sense considering other 97s were 4.4

Post by **RickHaleParker** » 05 May 2019, 18:14

Peevarino wrote: ↑05 May 2019, 17:51 Really? I had read multiple places that the R was still 4.3 in 97. It made no sense considering other 97s were 4.4

Pull the cover off the ECM box and get the number off the ECM, the number you are looking for is in the format "0 261 20X XXX" .

Peevarino · Post by **Peevarino** » 05 May 2019, 20:12

I will tomorrow, only number I remember from it is 628

Post by **jreed** » 06 May 2019, 05:09

For what it's worth, the LED code reader works OK on the ECC in this car.
I'm not sure if I've got Motronic 4.3 or 4.4. I think it might be a 4.3.
I've got a '97 855 GLT wagon and the ECU is a 0261203936.

Peevarino · Post by **Peevarino** » 06 May 2019, 06:03

It’s 9 261 203 628

ETA it’s probably a 0 not a 9