I have a 2008 Mazda 5, I had a P0037 code, which is HO2S Heater Control Circuit Low Bank 1 Sensor 2. I checked the fuses and replaced the rear 02 sensor, but the code came back. Any suggestions how to fix it?
I have a 2008 Mazda 5, I had a P0037 code, which is HO2S Heater Control Circuit Low Bank 1 Sensor 2. I checked the fuses and replaced the rear 02 sensor, but the code came back. Any suggestions how to fix it?
the code means that the signal is low through the circuit. The O2 sensor is just part of the circuit.
You will need electrical schematics to trace the wires down, so you can check connectors and any wires for cuts or corrosion.
1. Remove rear O2 sensor connector inspect for poor connection (such as damaged/pulled-out pins, corrosion) since the sensor has been replaced check harness side.
2. Measure the voltage between rear HO2S terminal D (wiring harness-side, bottom left wire from rear of connector) and body GND with Key On. Is the voltage B+? Yes: Repair or replace the wiring harness for a possible short to power, clear codes and retest.
3. Inspect PCM connection (such as damaged/pulled-out pins, corrosion), if good clear codes, if codes return replace PCM.
