Note
Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Diagnostic system check-engine controls".
1) Inspect the engine coolant for the following. Is the result normal?
Refer to "1.Engine 1D.Cooling(RZ4E-TC) coolant inspection".
Yes
=>Go to Individual harness connector inspection.
No
Repair or replace as necessary.
1) Inspect for poor connections at the engine coolant temperature sensor harness connector (pins 1 and 2 of E20). Is the connection status normal?
2) Inspect for poor connections at the ECM harness connector (pins 3 and 28 of E4). Is the connection status normal?
Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
3) Are all of the results normal?
Yes
=>Go to Inspection for high resistance in engine coolant temperature sensor circuit.
No
Repair the connections as necessary.
1) Inspect the circuit between the ECM (pins 3 and 28 of E4) and the engine coolant temperature sensor (pins 1 and 2 of E20) for high resistance. Is the result normal?
Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
Replace the engine coolant temperature sensor.
Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) engine coolant temperature sensor removal".
Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) engine coolant temperature sensor installation".
No
Repair the circuit as necessary.
1) Clear the DTC with a scan tool.
2) Turn OFF the ignition switch for 30 seconds or more.
3) Start the engine.
4) Operate the vehicle under the conditions for running the DTC.
5) Observe the DTC information with a scan tool.