Code 45 - Rich Exhaust Indication
The ECM supplies a voltage of about .45 volt between circuit Nos. 412 and 413. The oxygen sensor varies the voltage from one volt (rich exhaust) to .10 volt (lean exhaust). The sensor acts like an open sensor circuit and produces no voltage when exhaust temperature is below 600°F (316°C). An open sensor circuit or cold sensor causes open loop operation. Code 45 is set when oxygen sensor signal at ECM CD connector terminal D7 is above .7 volts for one minute and time since engine start is one minute or more.
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- Grounding diagnostic test terminal with engine running activates the "Field Service Mode" and allows the ECM to confirm either open or closed loop operation.
- A steady light or "OPEN LOOP" indicates presence of fault. Grounding circuit No. 412 causes a low oxygen sensor signal voltage. If the ECM and wiring are okay, the ECM should recognize the low voltage, and confirm lean signal by turning "SERVICE ENGINE SOON" light for at least 15 seconds.
- Code 45 will not be set by a faulty O2 sensor. Code 45 indicates a rich exhaust condition and diagnosis should begin with these items: fuel pressure, leaking injector, oxygen sensor contamination, canister purge saturation, coolant sensor, MAP sensor, and TPS intermittent output.