Code 25, O2 CKT/Lean Exhaust Indicated

ECM supplies approximately .45 volt between ECM terminals OX and E1 (VIN 6). If voltage is measured with a 10-megohm DVOM, reading may be as low as .32 volt. The O2 sensor produces a varying voltage as engine reaches normal operating temperature. Voltage will vary between .1-.9 volt.

The O2 sensor will not produce voltage until sensor reaches 600°F (316°C). When sensor is less than this temperature, an open loop condition exists.

1. Code 25 sets when O2 sensor signal voltage on Black wire remains below .2 volt for one minute or more with system in closed loop.