Six months ago I installed an MS2pnp and an Innovate LC-2 wideband sensor on my modified but naturally aspirated '94. The install was successful and dyno tuned, but after driving it for a few months I decided to do some additional tuning... unfortunately when I hooked up my laptop I discovered that the MS is no longer getting a wideband signal. The LC-2 controller light is green (no error codes). I'm regretting that I don't have a gauge to verify if the controller is getting signal, but the wiring to the MS is sound as far as I could check it with a multimeter.

As part of troubleshooting I removed the sensor (visually it looks ok) and recalibrated it (calibration was successful per the controller light). So I'm wondering... can the sensor itself fail without the controller showing an error code? Anybody know the answer? I'm about to order a new Bosch sensor but am worried about the lack of error codes.

Thanks in advance for any info!

 

The O2 sensor is providing a varying voltage depending on the amount of oxygen in the exhaust. Measuring that voltage with a DMM at the ecu will tell you if the sensor is doing it's job.

 

Thanks! I also discovered that you can plug into the serial out port of the LC-2 controller and log sensor data directly. I did this and got a good AFR signal, so the sensor is ok.

I then did as you suggested and hooked up my multimeter to the DIN pin going into the MS2... bingo, got ~2.0V once the sensor had warmed up, so the problem was likely a flakey DIN connector (since the LC-2 controller is right next to the MS2).

I hooked it all back up and now the MS2 is getting a good AFR reading! I still suspect the DIN connector and will replace it if this occurs again.

Thanks for your advice!

 

Nice. Glad you got it sorted.