U1003

U1003 CAN COMM CIRCUIT

Description

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. ECM and VVEL control module are connected with two communication lines (CAN H line and CAN L line) and transmit/receive data. ECM shares information and links with the VVEL control module during operation.


DTC Logic


DTC DETECTION LOGIC

NOTE:
If DTC U1003 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607.
Refer to "DTC Logic" P0607.






DTC CONFIRMATION PROCEDURE


1. PRECONDITIONING

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10 V at idle.
- GO TO 2.

2. PERFORM DTC CONFIRMATION PROCEDURE

1.Turn ignition switch ON and wait at least 3 seconds.
2.Check DTC.
Is DTC detected?
YES- Go to "Diagnosis Procedure" .
NO- INSPECTION END


Diagnosis Procedure


1. CHECK VVEL CAN COMMUNICATION CIRCUIT

1.Turn ignition switch OFF.
2.Disconnect ECM harness connector.
3.Disconnect VVEL control module harness connector.
4.Check the continuity between ECM harness connector and VVEL control module harness connector.





5.Also check harness for short to ground and power.
Is the inspection result normal?
YES- GO TO 3.
NO- GO TO 2.

2. DETECT MALFUNCTIONING PART

Check the following.
- Harness connector E3, F1
- Harness for open or short between ECM and VVEL control module
- Repair open circuit, short to ground or short to power in harness or connectors.

3. CHECK INTERMITTENT INCIDENT

Refer to "Intermittent Incident" Intermittent Incident.
Is the inspection result normal?
YES- GO TO 4.
NO- Repair or replace.

4. REPLACE VVEL CONTROL MODULE

1.Replace VVEL control module. Refer to "Component Parts Location" Locations.
2.Go to "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (VVEL CONTROL MODULE) : Special Repair Requirement" Special Repair Requirement.
- GO TO 5.

5. PERFORM DTC CONFIRMATION PROCEDURE

1.Reconnect all harness connectors disconnected.
2.Turn ignition switch ON.
3.Erase DTC.
4.Perform DTC Confirmation Procedure.
See "DTC Logic" .
5.Check DTC.
Is the DTC U1003 displayed again?
YES - GO TO 6.
NO- INSPECTION END

6. REPLACE ECM

1.Replace ECM.
2.Go to "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (ECM) : Special Repair
Requirement".
- INSPECTION END