Unit with the provided Bosch sensor worked for several weeks then failed. Unsure of whether or not it’s the unit or the sensor and obviously don’t want to replace the sensor if I don’t have to. Was connected to a motorcycle but now currently have it on the bench.
Symptoms were / are, reading on the gauge stuck on 10.3. Does not fluctuate at all with RPM changes.
I found the troubleshooting guide and get the following results:
Test 1.
O2 sensor disconnected and power up device. Voltage of green wire during initial power up approx 0.13v, and stays at 0.13v constantly. If I run the green wire to the provided gauge it’s showing an AFR of 10.3.
Test 2.
O2 sensor connected and power up device. Same as above, voltage of green wire during initial power up approx 0.13v, and stays at 0.13v constantly. If I run the green wire to the provided gauge it’s showing an AFR of 10.3. O2 sensor does not warm up at all.
I have replicated the above tests on my workbench with a fully charged 12v battery and also undertaken the additional test below.
Additional test.
12v connected to the centre pins (2 and 4?) of the O2 sensor to test the heating element. No problem, O2 sensor heats up immediately.
Please advise where to go from here.