DR-5B Oxygen Sensor Circuit at Logic Module

1. With oxygen sensor electrical connector disconnected, place ignition switch in the Off position.
2. Disconnect black electrical connector from logic module.
3. Connect a digital voltmeter between logic module black electrical connector terminal No. 18 and ground.
4. Place ignition switch in the Run position and note voltmeter reading.
5. If voltmeter indicates at least .3 volts, check wiring from oxygen sensor to terminal No. 18 of logic module black electrical connector for an open circuit.
6. If voltmeter indicates 0 voltage, replace logic module.
CAUTION: Before replacing the logic module check the terminal in cavity No. 18 of the black connector to make sure it is not crushed causing a poor connection.