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
| • | 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
Set heater core pump validity to invalid.
Conditions for Clearing the DTC
| • | 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
| • | Possible over current or wire short to power line fault |
| • | Possible wire open or short to ground fault |
Reference Information
Electrical Information Reference
Circuit/System Verification
- Ignition ON, command the heater core pump ON and OFF.
- Observe the operation of heater core pump.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the heater core pump.
- Ignition ON, verify that a test lamp illuminates between the control circuit terminal 1 and ground.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the heater core pump. |
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and control circuit terminal 1.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the heater core pump. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for heater core pump replacement, setup, and programming
