Refer to "56.Steering Control 6A.Troubleshooting diagnostic system check-electric power steering controls".
1) Connect the scan tool.
2) Power up the scan tool. Does the scan tool power up?
Yes
=>Go to EPS motor control unit 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".
1) Turn ON the ignition switch.
2) Verify that communication can be established with the EPS motor control unit using the scan tool. Can communication with the EPS motor control unit be established?
Yes
Go to Intermittent conditions of electric power steering control system.
Refer to "207.Steering 20D.Symptom intermittent conditions of electric power steering control system".
No
=>Go to Central gateway control unit communication verification.
1) Verify communication with the central gateway control unit using the scan tool. Can communication with the central gateway control unit be established?
Yes
=>Go to Chassis CAN communication circuit communication verification.
No
Go to Lost communication with the central gateway control unit.
1) Verify that communication can be established with the following control modules using a scan tool. Can communication with all the control modules be established?
Yes
No
Go to Chassis CAN communication circuit inspection.
Refer to "64.Body Control 10I.Troubleshooting(Central GateWay) chassis CAN communication circuit inspection".
1) Inspect the following fuses for a blowout. Is the result normal?
Yes
=>Go to EPS motor control unit 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 for poor connections at the EPS motor control unit harness connector (pins 1 and 2 of C117, pins 1, 4, and 5 of C116). Is the connection status normal?
Refer to "RHD Power Assisted System" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Inspection for open circuit in EPS motor control unit battery power supply circuit.
No
Repair the connections as necessary.
1) Disconnect the EPS motor control unit harness connector (C117).
2) Connect a test lamp between the battery power supply circuit (pin 1 of C117) and the body ground. Does the test lamp illuminate?
Refer to "RHD Power Assisted System" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Inspection for open circuit in EPS motor control unit ignition power supply circuit.
No
Repair the open circuit or high resistance in the battery power supply circuit between the EPS 100A fuse and the EPS motor control unit (pin 1 of C117).
1) Disconnect the EPS motor control unit harness connector (C116).
2) Connect a test lamp between the ignition power supply circuit (pin 1 of C116) and the body ground.
Refer to "RHD Power Assisted System" in the ETM (wiring diagram). (Open using the ETM viewer.).
3) Turn ON the ignition switch. Does the test lamp illuminate?
Yes
=>Go to Inspection for open circuit in EPS motor control unit ground circuit.
No
Repair the open circuit or high resistance in the ignition power supply circuit between the EPS(IG1) 5A fuse and the EPS motor control unit (pin 1 of C116).
1) Connect a test lamp between the battery power supply circuit (pin 1 of C117) and the ground circuit (pin 2 of C117). Does the test lamp illuminate?
Refer to "RHD Power Assisted System" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Chassis CAN communication circuit inspection.
No
Repair the open circuit or high resistance in the ground circuit between the EPS motor control unit (pin 2 of C117) and the body ground.
1) Inspect the CAN Low circuit and CAN High circuit between the EPS motor control unit (pins 4 and 5 of C116) and the central gateway control unit (pins 2 and 1 of B41) for the following. Is the result normal?
Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 without DPD, RZ4E))" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to EPS motor control unit replacement.
No
Repair the circuit as necessary.
Note
Refer to "6.Steering 6B.Power Assisted System power steering unit removal".
Refer to "6.Steering 6B.Power Assisted System power steering unit disassembly".
Refer to "6.Steering 6B.Power Assisted System power steering unit reassembly".
Refer to "6.Steering 6B.Power Assisted System power steering unit installation".
Refer to "6.Steering 6B.Power Assisted System power steering unit setting".
Procedure completion
1) Securely connect the disconnected harness connectors.
2) Connect the scan tool.
3) Turn ON the ignition switch.
4) Verify that communication can be established with the EPS motor control unit using the scan tool. Can communication with the EPS motor control unit be established?
Yes
The system is normal.
No
=>Go to EPS motor control unit harness connector inspection.