Description of On-Board Diagnostics

1. DIAGNOSIS SYSTEM

a. INDICATOR CHECK
1. Turn the ignition switch to ON.





2. Check that the CRUISE MAIN indicator light comes on when the cruise control main switch is turned on, and that the indicator light goes off when the main switch is turned OFF.

HINT: If the indicator check result is not normal, proceed to troubleshooting for the combination meter section.

b. DTC CHECK






HINT: If a malfunction occurs in the No.1 vehicle speed sensors or actuator, etc. during cruise control driving, the ECU actuates AUTO CANCEL of the cruise control and turns ON and OFF the CRUISE MAIN indicator light to inform the driver of a malfunction. At the same time, the malfunction is stored in memory as a diagnostic trouble code.

c. OUTPUT OF DTC USING DIAGNOSIS CHECK WIRE
1. Turn the ignition switch ON.





2. Using SST, connect terminals Tc and E1 of DLC2.
SST 09843-18020
3. Read the DTC on the CRUISE MAIN indicator light.






HINT: If the DTC is not output, inspect the diagnosis circuit. As an example, the blinking patterns for codes; normal, 11 and 21 are shown in the illustration.

2. ECU TERMINAL VALUES MEASUREMENT BY USING LEXUS BREAK-OUT-BOX AND LEXUS HAND-HELD TESTER





a. Hook up the break-out-box and LEXUS hand-held tester to the vehicle.
b. Read the ECU input/output values by following the prompts on the tester screen.
c. Please refer to the LEXUS hand-held tester has a "Snapshot" function. This records the measured data and is effective in the diagnosis of intermittent problems.





3. USING LEXUS HAND-HELD TESTER
a. Hook up the LEXUS hand-held tester to the DLC2.
b. Monitor the ECU data by following the prompts on the tester screen.

HINT: LEXUS hand-held tester has a "Snapshot" function which records the monitored data. Please refer to the LEXUS hand-held tester operator's manual for further details.