For 1990-2009 cars only
Diagnostic Instructions
| • | 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. |
DTC Descriptor
DTC B1439: Intermittent Device Voltage Range PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ | B1439 | B1439 | -- | -- |
Ground | -- | B1439 | -- | -- |
Circuit/System Description
The Heater Coolant Heater Control Module (HCHCM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.
Conditions for Running the DTC
| • | The voltages supplied to the control module is between 9.5-18 V. |
| • | The ignition is ON. |
| • | The engine is running. |
Conditions for Setting the DTC
HCHCM detects a intermittent system voltage concern.
Action Taken When the DTC Sets
The control module immediately disables all outputs when an out of range voltage condition has been detected.
Conditions for Clearing the DTC
The DTC clears when the system voltage returns to a normal range.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Air Temperature Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Diagnostic Aids
| • | A high or low voltage DTC 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 voltage value in multiple modules indicates a concern in the charging system. |
| • | Inspect G400 for corrosion and proper torque. |
Circuit/System Verification
- Observe the scan tool Auxiliary Heater Control Module, System Voltage High, System Voltage Low, DTC Set This Ignition parameters will assist you to verify if the fault is present.
- Verify that DTC B1439 is set as current.
- Engine running measure and record the voltage at the battery terminals.
- Verify that the battery voltage is 12.6-15.5 V.
- Observe the scan tool Auxiliary Heater Control Module ignition signal parameter.
- The battery terminal and AHCM parameter should not differ by more than 2 V.
- Ensure the harness connections at the module are fully seated and secure, inspect for bent terminals and corrosion.
| ⇒ | If the battery voltage is not within the specified range, refer to Charging System Test. |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the Heater Coolant Heater Control Module (HCHCM).
- Ignition OFF, test for less than 3.0 Ω between the ground circuit terminal H X2 and ground.
- Ignition ON , verify a test lamp illuminates between the B+ voltage circuit terminal A X2 and ground.
- If all circuits test normal, replace the Heater Coolant Heater Control Module.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ voltage circuit for a short to ground or an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
