Test KE: Step 21

21) Code 48: Check For High Flow of Unmetered Air  Code 48 indicates that measured airflow at base idle was higher than ECA specification. Possible causes for this fault are: air/vacuum leaks in fuel charging system or loss of ignition or fuel.

Check for and repair holes, cracks, and/or bad connections at air cleaner outlet tube (between vane airflow meter and fuel charging assembly). Check for loss of ignition or injection on one or more cylinders. If any faults are found, service as necessary. Rerun QUICK TEST. If no faults are found, EEC-IV system control of metered airflow is okay. Service other codes as necessary.