Engine Control System
DTC U0293 LOST COMMUNICATION WITH HV ECUCIRCUIT DESCRIPTION
DTC Detecting Condition:
The Controller Area Network (CAN) is a serial data communication system for real-time application. It is a multiplex communication system designed for on-vehicle use that provides a superior communication speed of 500 kbps and a capability to detect malfunction. Through the combination of the CANH and CANL bus lines, the CAN is able to maintain communication based on differential voltage.
HINT:
- Malfunction in the CAN bus (communication line) can be checked through the DLC3 connector, except in case of an open circuit in the DLC3 sub bus line.
- DTCs pertaining to CAN communication can be accessed through the use of the intelligent tester II (with CAN extension module).
- Malfunction in the DLC3 sub bus line cannot be detected through CAN communication, even though the DLC3 connector is connected to CAN communication.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
The ECM and the HV control ECU are connected through a set of communication lines on the CAN, in order to maintain mutual communication. The ECM uses the communication lines to transmit the engine speed or other pieces of information to the HV control ECU. The HV control ECU transmits signals such as a engine torque request signal to the ECM.
A few seconds after the power switch is turned ON, the ECM starts checking for any malfunction in the communication with the HV ECU. If the ECM detects a malfunction in the communication, the ECM sets a DTC and illuminates the MIL.
System Diagram:
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine condition when malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.