HO2S Heater Inspection

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

WARNING:

A hot engine and exhaust system can cause severe burns. Turn off the engine and wait until they are cool before removing the exhaust system.

CAUTION:

Do not allow flammable objects such as the taping for bundling a wiring harness to come into contact with the exhaust manifold and silencer.

Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .)
Disconnect the HO2S connector. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
Measure the resistance between HO2S terminals C and D.

Courtesy of MAZDA MOTORS CORP.

If not as specified, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)

HO2S heater resistance

2-50 ohms [normal temperature]