A/F Sensor Heater Circuit Open/Short Inspection

Fig 1: Identifying A/F Sensor, PCM And Main Fuse Block Connector Terminals

G05981147

Courtesy of MAZDA MOTORS CORP.

Disconnect the PCM connector.
Disconnect the A/F sensor connector.
Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

Open circuit

If there is no continuity, there is an open circuit. Repair or replace the wiring harness.

A/F sensor terminal C and main relay terminal C
A/F sensor terminal D and PCM terminal 2BG

Short circuit

If there is no continuity, there is a short circuit. Repair or replace the wiring harness.

A/F sensor terminal C and body ground
A/F sensor terminal D and power supply
A/F sensor terminal D and body ground