P1464

DTC P1464 Main Relay Performance

Circuit Description

The DEF control module internal main relay is energized to feed the battery voltage to the DEF control module when the DEF control module receives an ignition voltage switch ON signal. When the ignition switch is OFF, the main relay is de-energized after a certain length of time passed. If the DEF control module detects that the main relay command state and the control module ON/ OFF state are out of correlation, this DTC will set.

Condition for Running the DTC

Relay Stuck ON Error

- The ignition switch is OFF.

Control Module Shutdown Error

- The battery voltage is between 10 to 16 volts.
- The ignition switch is ON.

Condition for Setting the DTC

Relay Stuck ON Error

- The DEF control module detects that the main relay does not turn OFF when the relay is commanded OFF.

Control Module Shutdown Error

- The DEF control module detects a shutdown condition when the main relay is commanded ON.

Action Taken When the DTC Sets

Relay Stuck ON Error

- The DEF control module requests the ECM to illuminate the SVS. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type C.
- The DEF control module and the ECM apply defaulted warning actions. Refer to Default Action and Fail-Safe List.

Control Module Shutdown Error

- Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type D.

Conditions for Clearing the DTC

Relay Stuck ON Error

- Refer to DTC Type Definitions for Conditions for Clearing the DTC - Type C.

Control Module Shutdown Error

- Refer to DTC Type Definitions for Conditions for Clearing the DTC - Type D.

Diagnostic Aids

- If an intermittent condition is suspected, refer to Intermittent Conditions in this section.

Test Description

The number below refers to the step number on the Circuit/ System Testing.
3. If DTC P1463 is not set in the ECM, the DEF control module internal main relay is stuck ON. Replace the DEF control module.

Circuit / System Testing DTC P1464