HO2S Heater Resistance Inspection

WARNING: This page is about a different car, the 2004 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect the HO2S (front or rear) connector.
Measure the resistance between the following HO2S terminals.
- HO2S (Front, RH) and HO2S (Rear, RH)
  - Terminal C and D
- HO2S (Front, LH) and HO2S (Rear, LH)
  - Terminal C and D
- If not as specified, replace the HO2S.
- If the HO2S heater is okay, but PID value or any of PCM terminal 94, 93, 95, 96 voltage are out of specification, perform Circuit Open/Short Inspection .
Specification

Front (RH, LH): 5.0-6.8 ohms

Rear (RH, LH): 14.1-18.9 ohms