CAN Communication System

NETWORKING: CAN COMMUNICATION SYSTEM: U0100: Lost Communication with ECM / PCM "A"
U0100 - Lost Communication with ECM / PCM "A"

DESCRIPTION





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT
Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistance of the CAN main wire or CAN branch wire.

CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NOTICE:
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 FOR OPEN IN CAN BUS WIRE (ECM CAN MAIN WIRE)

(a) Disconnect the A35 ECM connector.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE ECM CAN MAIN WIRE OR CONNECTOR (CANP, CANN)
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ECM - BATTERY AND BODY GROUND)

(a) Connect the cable to the negative (-) battery terminal.

NOTICE:
When disconnecting the cable, some systems need to be initialized after the cable is reconnected Repair Instruction - Initialization.





Text in Illustration





(b) Disconnect the B30 ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal