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A/F Sensor Heater Inspection

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 cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION .)
Disconnect the A/F sensor connector.
Measure the resistance between A/F sensor terminals A and E.

Fig 1: A/F Sensor Connector
Courtesy of MAZDA MOTORS CORP.
- If not as specified, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION .)
  A/F sensor heater resistance
  
  1-10 ohms [normal temperature]