High CO, Low or Normal HC - At High RPM

This condition is indicated by abnormally high carbon monoxide with low or normal hydrocarbon emissions during cruise (2500 rpm).


POSSIBLE CAUSE ACTION


ECCS system malfunction. Refer to On Board Diagnostics. Computers and Control Systems



Faulty canister purge system. Check evaporative emissions system. Evaporative Emissions System





PCV malfunction. Check PCV system. Positive Crankcase Ventilation





EGR malfunction. Check EGR system. Exhaust Gas Recirculation



Restricted exhaust. Check catalytic converter. Catalytic Converter





Verify vehicle remains in
closed loop at steady throttle
(2000 rpm) and Heated Oxygen Sensors
are working. Oxygen Sensor