Computers and Control Systems: Service Precautions

PRECAUTIONS FOR OPERATION
a) Where battery voltage is low no detection of abnormality is made. Be sure to check the battery for conditions before starting the test.
b) Diagnosis item is erased if power supply from the battery or the ECU connector is disconnected. Do not disconnect power supply from battery before the diagnosis result is completely read.
c) Warm up engine and drive a good distance before oxygen sensor is diagnosed. Do not set ignition switch to OFF after driving. If ignition switch is set to OFF, the result detected by diagnosis is erased.
d) After check and correction are over, disconnect ground cable for 15 seconds or more from negative terminal of battery and connect it again to make sure that abnormal code is erased.