Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Diagnostic system check-engine controls".
1) Connect the scan tool.
2) Turn OFF the ignition switch for 30 seconds or more.
3) Turn ON the ignition switch.
4) Observe the DTC information with a scan tool. Is a DTC set?
Yes
=>Go to Cruise control main switch operation signal input check.
No
Go to Intermittent conditions of engine.
Refer to "202.Engine 15D.Symptom(RZ4E-TC) intermittent conditions of engine".
1) Turn OFF the ignition switch.
2) Disconnect the cruise control steering wheel switch harness connector (B34).
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) Turn ON the ignition switch.
4) Observe the Cruise Main Switch parameter on the scan tool. Does the Cruise Main Switch parameter display OFF?
Yes
Replace the cruise control steering wheel switch.
Refer to "9.Body, Cab, Accessories 9C.Electrical Control, Entertainment cruise control steering wheel switch removal".
No
=>Go to Inspection for short to power supply in cruise control main switch signal circuit.
1) Inspect the cruise control main switch signal circuit between the ECM (pin 25 of C7) and the cruise control steering wheel switch (pin 10 of B34) for a short to the battery power supply circuit or a short to the ignition power supply circuit. 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
No
Repair the circuit as necessary.
Note
Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM removal".
Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM installation".
Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM setting".
Procedure completion
1) Clear the DTC with a scan tool.
2) Turn OFF the ignition switch for 30 seconds or more.
3) Turn ON the ignition switch.
4) Operate the switch while observing the Cruise Main Switch parameter on the scan tool. Is ON displayed when the switch is operated and OFF when it is released?
Yes
Observe the DTC information with a scan tool.
No
=>Go to Cruise control main switch operation signal input check.