• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
B+ | P0622 | P0622 | -- | -- |
Field Duty Cycle Signal | P0622 | P0622 | -- | -- |
Charge Indicator Signal | P0621 | -- | P0621 | -- |
The engine control module (ECM) uses the charge indicator signal circuit, or L-terminal circuit, to control the load of the generator 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. The ECM monitors the state of the charge indicator signal circuit.
• | The engine is running. |
• | No generator, CKP sensors, CMP sensor DTCs are set. |
The charge indicator signal circuit is shorted to ground or shorted to voltage for 20 seconds.
• | The charge indicator turns ON. |
• | The driver information center (DIC) displays the SERVICE BATTERY CHARGING SYSTEM message. |
• | The DTC will pass when the condition for setting the DTC is no longer present for 2 seconds. |
• | A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
• | The charge indicator and DIC message will remain ON until the DTC passes or is cleared, even if the ignition is cycled. |
Starting and Charging Schematics
Charging System Description and Operation
Control Module References for scan tool information
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming. |