General Information

Engine Control
P2501 AMS Voltage Rationality - General Information

Component Location





General Description

Many control units have applied to vehicle as it becomes more eletrolnical. These units control their own system based on information from diverse sensors. Therefore necessity of common use of diverse sensor information and importance of stable power supply are gathering strength. Battery sensor is mounted on battery (-) terminal. It transmits battery voltage, current, temperature information to ECM. ECM controls generating voltage by duty cycle based on these signals.

DTC Description

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

DTC Detecting Condition





Diagnostic Circuit Diagram





Signal Waveform & Data
















Fig1.) Normal waveforms of IG, L terminal of alternator during charge warning lamp is ON
Fig2.) Normal waveforms of IG, L terminal of alternator during charge warning lamp is OFF
Fig3.) Normal waveforms of COM, FR terminal of alternator at idle.
Fig4.) Normal waveforms of COM, FR terminal of alternator under connector disconnected condition.