As we’ve talked about before in this column, the oxygen sensors are "messengers" that tell the vehicle’s ECM if the fuel mixture is correct, if there are intake vacuum leaks, coolant temperature not reaching normal and other information. If the "message" isn’t within encoded ECM limits, the ECM sets a diagnostic trouble code (DTC) and turns on the check engine light to inform the driver that "something" is wrong with engine management. We people all the time to please not "shoot the messenger" for telling them what it sees to be a problem requiring more diagnosis. It is probably time for a professional technician to perform some diagnostic routines until the exact problem is pinpointed.
Jim O’Neill
Chino Autotech Inc.
