U0100

DTC U0100 Lost Communication With Engine Control Module

Circuit Description

The DEF control module and the engine control module (ECM) communicate control and diagnostic information via the ISO-CAN 500 kbps transmission speed communication bus. The DEF control module monitors CAN operational status by receiving constant flow of messages from the ECM. If the DEF control module fails to receive constant messages from the ECM, this DTC will set. If the DEF control module sets CAN bus Off status, this DTC will also set.

Condition for Running the DTC

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

Condition for Setting the DTC

Either of following condition is met:
- The DEF control module detects that the CAN bus messages from the ECM are not being received longer than 3 seconds.
- The DEF control module detects the CAN communication bus OFF status longer than 3 seconds.

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC

- Refer to DTC Type Definitions for Conditions for Clearing the DTC - Type A or Type B.

Diagnostic Aids

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

Circuit / System Testing DTC U0100