Mazda CX-9 Grand Touring 2009 Manual page 848

Fig. 27: Output Voltage Graph
Courtesy of MAZDA MOTORS CORP.
If not within the specification, inspect the front HO2S for an open or short circuit. (See FRONT
HEATED OXYGEN SENSOR (HO2S) Voltage Inspection.) Then if there is no malfunction in
the wiring harness, replace the front HO2S. (See FRONT HEATED OXYGEN SENSOR
(HO2S) REMOVAL/INSTALLATION [MZI-3.7].)
HO2S HEATER RESISTANCE INSPECTION
1. Disconnect the HO2S connector.
2. Measure the resistance between HO2S terminals C and A.
If it is not within the specification, replace the HO2S. (See FRONT HEATED OXYGEN
SENSOR (HO2S) REMOVAL/INSTALLATION [MZI-3.7].)
If the monitor item status/specification (reference) is not within the specification, even though the
resistance is within the specification, perform the "Circuit Open/Short Inspection".
HO2S heater resistance
3-30 ohms
2008 Mazda CX-9 Grand Touring
2008 ENGINE Control System (MZI-3.7) - Mazda CX-9