Diagnostic Instructions
DTC Descriptor
DTC B3844: Heater Core Pump Circuit
Circuit/System Description
The starter/generator control module (SGCM) monitors the heater core pump control circuit for an open wire or a over current condition.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
B3844
| • | Eco-back signal (High) does not match to the LSD output signal for 320 ms. |
| • | Eco-back signal (Low) does not match to the LSD output signal for 320 ms. |
Action Taken When the DTC Sets
B3844
Set heater core pump validity to invalid.
Conditions for Clearing the DTC
B3844
| • | LSD over current fault removed. |
| • | Clears 30 seconds after cycle wake up signal. |
| • | LSD wire open fault removed. |
| • | Normal range for 3.5 seconds. |
Diagnostic Aids
B3844
| • | Possible over current or wire shorted to B+. |
| • | Possible wire open or shorted to ground . |
Reference Information
Schematic Reference
Hybrid Cooling Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
Circuit/System Verification
- Ignition ON, command the heater core pump ON and OFF with a scan tool.
- Observe the operation of heater core pump.
Circuit/System Testing
B3844
- Ignition OFF, disconnect the harness connector at the heater core pump.
- Ignition ON, verify that a test lamp illuminates between the control circuit terminal B and B+, while commanding the pump ON and OFF with a scan tool.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to Ground. If the circuit tests normal, replace the Starter Generator Control Module (SGCM). |
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and control circuit terminal B, while commanding the pump ON and OFF with a scan tool.
| ⇒ | The test lamp should be ON and Off with each commanded state, if the test lamp is always OFF, test the B+ circuit for an open or short to ground. If the test lamp operates properly with each command, replace the heater core pump. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for SGCM replacement, setup, and programming
Heater Coolant Pump Replacement
