Diagnostic Instructions
DTC Descriptors
DTC B1420 00: Device Voltage Circuit
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
B+ / IGN
| B1420 00
| B1420 00
| --
| --
|
Ground
| --
| B1420 00
| --
| --
|
Circuit/System Description
The body control module (BCM) monitors the battery voltage through the battery voltage signal circuit. If the BCM senses that battery voltage is outside of its normal range, DTC B1420 will set. Damage to components, and incorrect data may occur
when the voltage is out of range.
Conditions for Running the DTC
| • | The voltage supplied to the BCM are in the range of 7-26 volts. |
Conditions for Setting the DTC
| • | The BCM senses a battery voltage above or below the specified range of 9-16 volts. |
| • | The above condition lasts for 1 second. |
Action Taken When the DTC Sets
| • | The BCM will disable all its outputs when a high voltage condition is detected. |
| • | The setting of this DTC inhibits the setting of other DTCs. |
Conditions for Clearing the DTC
The DTC clears when the system voltage returns to a normal range.
Reference Information
Schematic Reference
Body Control System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Diagnostic Aids
| • | A high or low voltage DTC set in multiple modules indicates a concern in the charging system. |
| • | A possible cause of this DTC could be overcharging with a battery charger or jump starting. |
| • | A high or low voltage value in multiple modules indicates a concern in the charging system. |
Circuit/System Verification
- Engine running measure and record the voltage at the battery terminals. Verify that the battery voltage is 12.5-15.5 volts.
- Engine running, observe the scan tool BCM Battery Positive Voltage parameter. Verify that the scan tool displays a value that is within 2 volts of the battery terminal voltage.
Circuit/System Testing
- Ignition OFF. Disconnect the harness connectors at the BCM.
- Ignition OFF, test for less than 5.0 ohms between the BCM ground circuit terminals listed below and ground.
| ⇒ | If greater than the specified value, test the ground circuits for an open/high resistance. |
- Ignition ON, verify a test lamp between the B+ / IGN circuits terminals listed below and ground.
| ⇒ | If the test lamp does not illuminate , test the B+ / IGN circuits for a short to ground or an open/high resistance. |
- If all the circuits test normal, replace the BCM.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for BCM replacement, setup, and programming.
