Normally, battery voltage fluctuates from 11.5V to 14.5V. Especially at cranking, voltage can drop to 9.8V. Therefore, actuators which require 12V power supply meet fluctuation of power by 5V. A little change of voltage supply can shift controlling characteristic of actuators, such as injectors, RPV and EGR actuator, which should be controlled delicately. To correct controlling characteristic change arrived from voltage fluctuation, ECM performs actuator operating correction according to voltage change as detecting battery voltage change.

P0562 is set when battery voltage below 6V is detected for more than 5 sec. Check charging system. (charging circuit, alternator component) ☞ ECM senses battery voltage as monitoring the voltages in 'Engine control relay ON' terminal.

Fig 1) This is alternator charging waveform during engine running.

☞ Check if battery voltage drops dramatically as turning on the electrical device such as head lamp, defogger and A/C.