General Information

Engine Control
P2502 Battery Voltage Rationality - General Information

Component Location





General Description

Battery sensor is mounted on the battery (-) terminal. It transmits battery voltage, current, temperature information to PCM. PCM controls the generating output by changing the duty cycle to the generator based on these signals.

DTC Description

PCM sets this code when there is difference between battery voltage at power supply terminal of PCM and PCM commend voltage.

DTC Detecting Condition





Diagnostic Circuit Diagram










Signal Waveform & Data








Fig.1) Normal waveforms of COM, FR terminal of alternator at idle.
Fig.2) Normal waveforms of COM, FR terminal of alternator under high electronic load condition
- When the eletronic load (head lamp, room lmap. ) is applied, the duty(+) value of the FR line is increased.