Part 1

CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: U1004: Lost Communication with Engine Gateway Module

DTC U1004 - Lost Communication with Engine Gateway Module

DESCRIPTION

If 2 or more DTCs are output during the DTC check, one side of the CAN branch wire may be open. (One side of the CANH [branch wire]/CANL [branch wire] of the ECU and/or sensor is open.)

HINT: *1: w/ Dynamic Radar Cruise Control System or Pre-collision System
*2: w/ Advanced Parking Guidance System and Intuitive Parking Assist System
*3: w/ Intuitive Parking Assist System
*4: w/ Active Stabilizer Suspension System

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.
CAUTION: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to prevent airbag and seat belt pretensioner activation.
CAUTION:
- After the power switch is turned OFF, the HDD navigation system requires approximately 6 minutes to record various types of memory and settings. As a result, after turning the power switch OFF, wait 6 minutes or more before disconnecting the cable from the negative (-) battery terminal.
- When disconnecting the cable, some systems need to be initialized after the cable is reconnected Repair Instruction - Initialization.

NEXT -- Continue to next step.
2. CHECK CAN BUS WIRE (MAIN WIRE FOR DISCONNECTION, BUS LINES FOR SHORT CIRCUIT)

(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:

C -- CHECK HARNESS AND CONNECTOR (ECM - BATTERY AND BODY GROUND)
B -- CHECK FOR SHORT IN CAN BUS WIRES (NO. 7 JUNCTION CONNECTOR SIDE)
A -- Continue to next step.
3. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 7 JUNCTION CONNECTOR - ELECTRIC PARKING BRAKE ECU)

(a) Disconnect the A66 No. 7 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- CONNECT CONNECTOR
OK -- Continue to next step.
4. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 7 JUNCTION CONNECTOR - POWER STEERING ECU)

(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- CONNECT CONNECTOR
OK -- REPLACE NO. 7 JUNCTION CONNECTOR
5. CONNECT CONNECTOR
(a) Reconnect the A66 No. 7 junction connector connector.
NEXT -- Continue to next step.
6. CHECK FOR OPEN IN CAN BUS MAIN WIRE (POWER STEERING ECU - NO. 7 JUNCTION CONNECTOR)

(a) Disconnect the A44 power steering ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO POWER STEERING ECU (POWER STEERING ECU - NO. 7 JUNCTION CONNECTOR)
OK -- REPLACE POWER STEERING ECU
7. CONNECT CONNECTOR
(a) Reconnect the A66 No. 7 junction connector connector.
NEXT -- Continue to next step.
8. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 6 JUNCTION CONNECTOR - NO. 7 JUNCTION CONNECTOR)

(a) Disconnect the A86 No. 6 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 6 JUNCTION CONNECTOR - NO. 7 JUNCTION CONNECTOR)
OK -- Continue to next step.
9. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 6 JUNCTION CONNECTOR - ELECTRIC PARKING BRAKE ECU)

(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- CONNECT CONNECTOR
OK -- REPLACE NO. 6 JUNCTION CONNECTOR
10. CONNECT CONNECTOR
(a) Reconnect the A86 No. 6 junction connector connector.
NEXT -- Continue to next step.
11. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 4 JUNCTION CONNECTOR - NO. 6 JUNCTION CONNECTOR)

(a) Disconnect the S73 No. 4 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 4 JUNCTION CONNECTOR - NO. 6 JUNCTION CONNECTOR)
OK -- Continue to next step.
12. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 4 JUNCTION CONNECTOR - ELECTRIC PARKING BRAKE ECU)

(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- CONNECT CONNECTOR
OK -- REPLACE NO. 4 JUNCTION CONNECTOR
13. CONNECT CONNECTOR
(a) Reconnect the S73 No. 4 junction connector connector.
NEXT -- Continue to next step.
14. CHECK FOR OPEN IN CAN BUS MAIN WIRE (ELECTRIC PARKING BRAKE ECU - NO. 4 JUNCTION CONNECTOR)

(a) Disconnect the S48 electric parking brake ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO ELECTRIC PARKING BRAKE ECU (ELECTRIC PARKING BRAKE ECU - NO. 4 JUNCTION CONNECTOR)
OK -- REPLACE ELECTRIC PARKING BRAKE ECU
15. CHECK FOR SHORT IN CAN BUS WIRES (NO. 7 JUNCTION CONNECTOR SIDE)

(a) Disconnect the A66 No. 7 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- CONNECT CONNECTOR
OK -- Continue to next step.
16. CHECK FOR SHORT IN CAN BUS WIRES (NO. 7 JUNCTION CONNECTOR - SUSPENSION CONTROL ECU)