Problem Symptoms Table
WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.
If a normal system code is displayed during the DTC check but the problem still occurs, check the suspected areas for each problem symptom in the order given in the table below and proceed to the relevant troubleshooting page.
HINT:
Inspect the "Fuse" and "Relay" before confirming the suspected areas as shown in the chart below.
Inspect each suspected area for the corresponding symptom in numerical order.
PROBLEM SYMPTOMS
| Symptom | Suspected Area | See |
|---|---|---|
| Main switch cannot be turned ON. (Cruise indicator light in combination meter does not come on.) |
|
CRUISE CONTROL SWITCH CIRCUIT CRUISE MAIN INDICATOR LIGHT CIRCUIT REPLACEMENT |
| Vehicle speed setting cannot be done. (Although indicator light in combination meter comes on when the main switch is turned ON, it goes off when vehicle speed is set.) |
|
CRUISE CONTROL SWITCH CIRCUIT REPLACEMENT |
| Setting cannot be done. (Indicator light in combination meter comes on when the main switch is turned ON and it remains ON while setting.) |
|
CRUISE CONTROL SWITCH CIRCUIT DTC P0571 STOP LIGHT SWITCH CIRCUIT MALFUNCTION COMPONENT OPERATING RANGE INSPECTION PROCEDURE SEAT BELT WARNING LAMP FOR DRIVER'S SEAT DOES NOT OPERATE REPLACEMENT |
| While the vehicle is driven with cruise control, the set control is cancelled. (Indicator light and CRUISE remain ON.) |
|
CRUISE CONTROL SWITCH CIRCUIT TYPICAL ENABLING CONDITIONS DTC P0571 STOP LIGHT SWITCH CIRCUIT MALFUNCTION CRUISE MAIN INDICATOR LIGHT CIRCUIT COMPONENT OPERATING RANGE REPLACEMENT |
| Hunting (Speed is not constant.) |
|
TYPICAL ENABLING CONDITIONS PROBLEM SYMPTOMS TABLE LASER SENSOR POWER SOURCE CIRCUIT DISTANCE CONTROL ECU POWER SOURCE CIRCUIT REPLACEMENT REPLACEMENT |
| Setting cannot be cancelled. (When Coast, Acceleration, Resume, Set speed change and Control switch are operated.) |
|
CRUISE CONTROL SWITCH CIRCUIT REPLACEMENT |
| Erroneous detection or lost sight of the vehicle ahead. |
|
- ADJUSTMENT |
| Alarm buzzer does not sound. |
|
WIRING DIAGRAM CUSTOMER PROBLEM ANALYSIS CHECK LASER SENSOR POWER SOURCE CIRCUIT DISTANCE CONTROL ECU POWER SOURCE CIRCUIT REPLACEMENT REPLACEMENT |
| Set distance cannot be changed. |
|
SEAT BELT WARNING LAMP FOR DRIVER'S SEAT DOES NOT OPERATE DISTANCE CONTROL SWITCH CIRCUIT CRUISE CONTROL SWITCH CIRCUIT REPLACEMENT |
| No display |
|
SEAT BELT WARNING LAMP FOR DRIVER'S SEAT DOES NOT OPERATE REPLACEMENT |
| No brake control (when decelerating) |
|
CUSTOMER PROBLEM ANALYSIS CHECK DISTANCE CONTROL ECU POWER SOURCE CIRCUIT REPLACEMENT REPLACEMENT |
| Constant speed mode cannot be turned on. |
|
CRUISE CONTROL SWITCH CIRCUIT SEAT BELT WARNING LAMP FOR DRIVER'S SEAT DOES NOT OPERATE REPLACEMENT |
| Vehicle speed setting cannot be cancelled with wiper LO/HI. (Including automatic wiper) |
|
ON-VEHICLE INSPECTION CUSTOMER PROBLEM ANALYSIS CHECK REPLACEMENT REPLACEMENT |
| Setting cannot be cancelled in SNOW mode. |
|
INSPECTION PROCEDURE CUSTOMER PROBLEM ANALYSIS CHECK REPLACEMENT |
| Unable to adjust (complete) the optical axis of the laser sensor. |
|
DTC P1570 RADAR SENSOR MALFUNCTION ADJUSTMENT - LASER SENSOR REPLACEMENT |