Captiva

DTC P2501

The engine control module (ECM) uses the alternator turn on signal circuit to control the load of the alternator on the engine. A high side driver in the ECM applies a voltage to the voltage regulator. This signals the voltage regulator to turn the field circuit ON and OFF. When the ECM turns ON the high side driver, the voltage regulator turns ON the field circuit. When the ECM turns OFF the high side driver, the voltage regulator turns OFF the field circuit.

The ECM monitors the state of the generator turn on signal circuit. The ECM should detect a low alternator turn on signal circuit voltage when the Ignition is ON and the engine is OFF, or when the charging system malfunctions. If the ECM detects a high alternator turn on signal circuit voltage, DTC P2501 will set.

The ECM detects a high signal voltage on the alternator turn on signal circuit for at least 5 seconds.

DTC P2501 is a C type DTC.

DTC P2501 is a C type DTC.

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Charging System Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information.

1. Ignition OFF, disconnect the harness connector at the generator.
2. Ignition ON, test for less than 1 volt between the alternator turn on signal circuit terminal and ground.

⇒	If greater than the specified range, test the alternator turn on signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

3. If the circuit tests normal, test or replace the generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.