1) Connect the scan tool.
2) Check whether the scan tool powers up. Does the scan tool power up?
Yes
=>Go to EHCU communication verification.
No
Go to Scan tool does not power up.
Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) Scan tool does not power up".
Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) Scan tool does not power up".
Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Scan tool does not power up".
1) Turn ON the ignition switch.
2) Verify communication with the EHCU using the scan tool. Can communication with the EHCU be established?
Yes
Go to Intermittent conditions of brake.
Refer to "205.Brakes 18D.Symptom intermittent conditions of brake".
No
1) Inspect the connection status of the DLC terminals (pins 6 and 14 of C19). Is the connection status normal?
Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
No
Repair the connections as necessary.
1) Inspect the following fuses for a blowout. Is the result normal?
Yes
=>Go to EHCU harness connector inspection.
No
Replace the fuse. If the fuse blows out again, repair the short to ground in the circuit relating to each fuse.
1) Inspect the connection status of the EHCU harness connector terminals (pins 1, 13, 25, 28, and 38 of C13). Is the connection status normal?
Refer to "RHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Inspect the EHCU power supply circuit and ground circuit..
No
Repair the connections as necessary.
1) Turn OFF the ignition switch.
2) Disconnect the EHCU harness connector (C13).
3) Inspect the wire harness for the following. Is the result normal?
Wire harness to be inspected
Inspection items
Refer to "RHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to CAN communication circuit inspection.
No
Repair the circuit as necessary.
1) Inspect the communication circuit between the DLC (pins 14 and 6 of C19) and the EHCU (pins 26 and 14 of C13) for the following. Is the result normal?
Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
No
Repair the circuit as necessary.
Note
Refer to "4.Brakes 4Z.Brake Electrical Control EHCU removal".
Refer to "4.Brakes 4Z.Brake Electrical Control EHCU installation".
Refer to "4.Brakes 4Z.Brake Electrical Control EHCU setting".
Procedure completion
1) Securely connect the disconnected harness connectors.
2) Connect the scan tool.
3) Turn ON the ignition switch.
4) Verify communication with the EHCU using the scan tool. Can communication with the EHCU be established?
Yes
The system is normal.
No