Bosch cj125 oxygen sensor interface

[efiLabs]

i'm currently working with a bosch cj125 and having problems with the Ri measurements.

i have seen a couple of posts related to oxygen sensors and was wondering if anyone has some experiences with it

the signal on pin UN appears to be distorted from the pump-current input at pin IA.

if there is anyone out there who worked with it it would be nice to share some thoughts.

i suspect that the chip is either internally damaged or the day code of the part i'm using has a problem.

also the bosch datasheet doesn't really explain which init1-reg bit to use for which phase of the sampling

i'm not asking for someone to do the design for me, just to share some common experiences

i would also be happy to post / share some embedded C++ code or other experiences with anyone who ever had their hands on a cj125 based project.

it's normally impossible to get any usable techie info from bosch unless you're mercedes, bmw or vw.

thanks and cheers, efiLabs

 

[efiLabs]

i finally found what was wrong ... it was me

when the sensor is cold the wave forms on the sensor, measured on the board connector looked all ok ... when i turned on the pwm heating, the signal on AI appeared to feed through the sensor or something inside the cj125.

it was a broken connection on VM inside my connector connecting to the sensor connector.

i feel a bit dumb, but the correct behavior when cold fooled me into the assumption that the wiring is good. and i had the VM signal from the board also as stable on the scope.

cheers, efiLabs