• | 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+ | B1390 | B1390 | -- | -- |
Ground | -- | B1390 | -- | -- |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Ignition ON, engine OFF. Parameter Normal Range: 12.6 Volts | |||
B+ | 0.0 Volts | 0.0 Volts | -- |
Ground | -- | 0.0 Volts | -- |
The generator battery control module (GBCM) monitors the battery voltage for precision electrical power management. The GBCM monitors both the battery sense positive voltage circuit and the battery sense negative, or ground, circuit to precisely determine system voltage. If there is a difference between the less precise battery voltage circuit and the more precise battery sense circuit of 1 volt or greater for 10 seconds, then DTC B1390 will set.
• | The ignition is ON. |
• | This diagnostic runs every 100 ms. |
The difference between the low precision battery voltage circuit reading and the high precision battery voltage sense circuit reading is greater than or equal to 1 volt for 10 seconds.
• | The driver information center (DIC) displays the BATTERY message. |
• | The GBCM uses the less accurate battery positive voltage circuit for voltage readings. |
This DTC will pass when the difference between the less precision battery positive voltage circuit reading and the high precision battery voltage sense circuit reading is less than 1 volt.
• | You must cycle the ignition after clearing the DTC to turn off the BATTERY DIC message. |
• | Overcharging with a battery charger or jump starting could cause this DTC to set. |
• | A high voltage value in multiple modules indicates a concern in the charging system. |
Starting and Charging Schematics
Charging System Description and Operation
Control Module References for scan tool information
⇒ | If not within the specified range, refer to Charging System Test . |
• | Terminal F |
• | Terminal H |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
• | Terminal A |
• | Terminal C |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for GBCM replacement, setup and programming.