B3844

DTC B3844

Circuit Description

The starter generator control module (SGCM) controls the transmission pump operation by applying voltage to the auxiliary transmission relay control circuit with an internal solid state device called a hybrid pump driver. When the SGCM is commanding the relay ON, the voltage of the control circuit should be high, near 12 volts. When the SGCM is commanding the relay OFF, the voltage potential of the control circuit should be low, near 0 volts.

The SGCM monitors the relay control circuits for the following conditions:

* Short to ground
* Short to voltage
* An open circuit

If the SGCM detects an improper voltage level on the hybrid pump driver circuit driver circuit, then DTC B3844 will set and the driver will be disabled.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3844 Engine Coolant Circulation Pump Circuit

Conditions for Running the DTC

* The ignition switch is in the RUN or CRANK position.
* Device power moding error.
* The ignition 0 voltage circuit input is within 8-16 volts.

Conditions for Setting the DTC

The SGCM determines the state of the auxiliary transmission pump relay control circuit is shorted to ground, open or shorted to power.

Action Taken When the DTC Sets

* The control module stores the DTC information into memory when the diagnostic runs and fails.
* The malfunction indicator lamp (MIL) will not illuminate.
* The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
* The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

* A current DTC Last Test Failed clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
* Clear the DTC with a scan tool.

Diagnostic Aids

If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

Test Description

Step 1 - Step 13:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible click when the auxiliary water pump relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. This step tests for voltage at the coil side of the auxiliary trans pump relay. The TRANS PUMP Maxi fuse supplies power to the coil side of the auxiliary trans pump relay.
4. This step verifies that the SGCM is providing ground to the auxiliary trans pump relay.
5. This step tests if ground is constantly being applied to the auxiliary trans pump relay.