Hard Failures

Hard failures cause CHECK ENGINE light to come on and trouble code(s) to be set in ECA memory. Trouble code(s) remain until problem is repaired. To retrieve trouble code(s), see RETRIEVING CODES in this article. Use diagnostic (code) charts to determine the cause of malfunction.

If a sensor fails, the ECA will use a substitute value in its calculations to continue engine operation. The ECA can estimate failed sensor values based on feedback from working sensor(s). In this condition, commonly known as Limited Operating Strategy (LOS), the vehicle runs but driveability will not be optimum.