20 LS430 − NEW FEATURES Diagnosis When the ECM detects a malfunction, the ECM makes a diagnosis and memorizes the failed section. Furthermore, the MIL (Malfunction Indicator Lamp) in the combination meter illuminates or blinks to inform the driver. At the same time, the DTC (Diagnosis Trouble Codes) are stored in memory. The DTC can be read by connecting a hand-held tester to DLC3. 2 Service Tip The ECM of the ’04 LS430 uses the CAN protocol for diagnostic communication. Therefore, a hand-held tester and a dedicated adapter [CAN VIM (Vehicle Interface Module)] are required for accessing diagnostic data. For details, see the 2004 LEXUS LS430 Repair Manual (Pub. No. RM1048U).
Fail Safe This function minimizes the loss of operability when any abnormality occurs in each sensor or solenoid. Fail-Safe Control List Malfunction Part Function Input Speed Sensor (NT) During an input speed sensor malfunction, shift control is effected through the output speed sensor signal (SP2). During an input speed sensor malfunction, up-shift to the 5th and 6th, AI-SHIFT and flex lock-up clutch control are prohibited. Output Speed Sensor (SP2) During an output speed sensor malfunction, shift control is effected through the input speed sensor signal (NT). During an output speed sensor malfunction, up-shift to the 5th and 6th, AI-SHIFT and flex lock-up clutch control are prohibited.
ATF Temp. Sensor During an ATF temperature sensor malfunction, up-shift to the 5th and 6th and flex lock-up clutch control are prohibited. Solenoid Valve S1, S2, S2, S4 and SR The current to the failed solenoid valve is cut off and control is effected by operating the other solenoid valves. Shift control is effected depending on the failed solenoid as described in the table on the next page. Solenoid Valve SL1 and SL2 During a solenoid valve SL1 or SL2 malfunction, up-shift to the 5th and 6th and flex lock-up clutch control are prohibited. Solenoid Valve SLU During a solenoid valve SLU malfunction, the current to the solenoid valve is stopped.
Because this stops lock-up control and flex lock-up control, fuel economy decreases. Solenoid Valve SLT During a solenoid valve SLT malfunction, the current to the solenoid valve is stopped. Because this stops line pressure optimal control, the shift shock increases. However, shifting is effected through normal clutch pressure control.