Problem Symptoms Table
WARNING: This page is about a different car, the 2007 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
HINT:
- Use the table below to help determine the cause of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "Suspected area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
- Inspect the fuse and relay related to this system before inspecting the suspected areas below.
Dynamic Laser Cruise Control System
PROBLEM SYMPTOMS TABLE
| Symptom | Suspected area | Information |
|---|---|---|
| Main switch cannot be turned on. (CRUISE main indicator light on combination meter does not illuminate.) | Cruise control switch circuit | CRUISE CONTROL SWITCH CIRCUIT |
| CRUISE main indicator light circuit | CRUISE MAIN INDICATOR LIGHT CIRCUIT | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| Vehicle speed setting cannot be done. (CRUISE main indicator light on combination meter illuminates when main switch is turned on, but turns off when operating SET function.) | Cruise control switch circuit | CRUISE CONTROL SWITCH CIRCUIT |
| If the symptoms still occur after the above area has been inspected and has proven to be normal, replace the ECM. | REMOVAL | |
| Vehicle speed setting cannot be done. (CRUISE main indicator light on combination meter illuminates when main switch is turned on, and remains on when operating SET function.) | Cruise control switch circuit | CRUISE CONTROL SWITCH CIRCUIT |
| Stop light switch circuit | DTC P0571: BRAKE SWITCH "A" CIRCUIT | |
| Park/Neutral position switch circuit | DTC P0705: TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT) | |
| Vehicle speed sensor circuit | DTC P0500, P0503: VEHICLE SPEED SENSOR MALFUNCTION; VEHICLE SPEED SENSOR "A" INTERMITTENT/ERRATIC/HIGH | |
| Pattern Select Switch Circuit (U151E) | PATTERN SELECT SWITCH CIRCUIT | |
| Pattern Select Switch Circuit (U151F) | PATTERN SELECT SWITCH CIRCUIT | |
| Combination meter system | HOW TO PROCEED WITH TROUBLESHOOTING | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| While vehicle is driven with cruise control, the control is canceled. (CRUISE main indicator light remains on.) | Cruise control switch circuit | CRUISE CONTROL SWITCH CIRCUIT |
| Vehicle speed sensor circuit | DTC P0500, P0503: VEHICLE SPEED SENSOR MALFUNCTION; VEHICLE SPEED SENSOR "A" INTERMITTENT/ERRATIC/HIGH | |
| Stop light switch circuit | DTC P0571: BRAKE SWITCH "A" CIRCUIT | |
| Combination meter system | HOW TO PROCEED WITH TROUBLESHOOTING | |
| Park/Neutral position switch circuit | DTC P0705 TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT) | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| Hunting (Speed is not constant.) | Vehicle speed sensor circuit | DTC P0500, P0503: VEHICLE SPEED SENSOR MALFUNCTION; VEHICLE SPEED SENSOR "A" INTERMITTENT/ERRATIC/HIGH |
| If the symptoms still occur after the above area has been inspected and has proven to be normal, replace the ECM. | REMOVAL | |
| Vehicle speed setting cannot be canceled. (When coast, acceleration, resume, or set speed change function is operated with control switch.) | Cruise control switch circuit | CRUISE CONTROL SWITCH CIRCUIT |
| If the symptoms still occur after the above area has been inspected and has proven to be normal, replace the ECM. | REMOVAL | |
| Erroneous detection or lost sight of the vehicle ahead. | Clean laser sensor with soft cloth, etc. | - |
| Improper aiming of sensor beam axis | REMOVAL | |
| Alarm buzzer does not sound. | Buzzer circuit | SKID CONTROL BUZZER CIRCUIT |
| VSC system | HOW TO PROCEED WITH TROUBLESHOOTING | |
| Distance control ECU power source circuit | DISTANCE CONTROL ECU POWER SOURCE CIRCUIT | |
| Distance control ECU | DISTANCE CONTROL ECU | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| Set distance cannot be changed. | Combination meter system | HOW TO PROCEED WITH TROUBLESHOOTING |
| Distance control switch circuit | CRUISE CONTROL SWITCH CIRCUIT | |
| Distance control ECU | DISTANCE CONTROL ECU | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| No information on the display | Combination meter system | HOW TO PROCEED WITH TROUBLESHOOTING |
| If the symptoms still occur after the above area has been inspected and has proven to be normal, replace the ECM. | REMOVAL | |
| No brake control (when decelerating) | VSC system | HOW TO PROCEED WITH TROUBLESHOOTING |
| Distance control ECU power source circuit | DISTANCE CONTROL ECU POWER SOURCE CIRCUIT | |
| Distance control ECU | DISTANCE CONTROL ECU | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| Constant speed mode cannot be turned on. | Cruise control switch circuit | CRUISE CONTROL SWITCH CIRCUIT |
| Combination meter system | HOW TO PROCEED WITH TROUBLESHOOTING | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| Vehicle speed cannot be canceled with wiper HI or LO. (Including automatic wiper) | Wiper motor circuit | FRONT WIPER MOTOR CIRCUIT |
| Wiper switch circuit | WIPER AND WASHER SWITCH CIRCUIT | |
| Distance control ECU | DISTANCE CONTROL ECU | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| Setting cannot be canceled in SNOW mode. | Pattern select switch circuit (U151E) | PATTERN SELECT SWITCH CIRCUIT |
| Pattern select switch circuit (U151F) | PATTERN SELECT SWITCH CIRCUIT | |
| Automatic transmission system | HOW TO PROCEED WITH TROUBLESHOOTING | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| Unable to adjust (complete) beam axis of laser sensor. | Check position, distance and angle of reflector | REMOVAL |
| Check installation of laser sensor | INSTALLATION | |
| Laser sensor | REMOVAL | |
| Distance control ECU | DISTANCE CONTROL ECU | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM | REMOVAL | |
| Cannot change from constant speed control mode to vehicle-to-vehicle distance control mode. | Cruise control switch circuit | CRUISE CONTROL SWITCH CIRCUIT |
| Laser sensor power source circuit | LASER SENSOR POWER SOURCE CIRCUIT | |
| Distance control ECU | DISTANCE CONTROL ECU | |
| If the symptoms still occur after the above areas have been inspected and have proven to be normal, replace the ECM. | REMOVAL | |
| The CRUISE main indicator light remains blinking. | TC and CG terminal circuit | TC AND CG TERMINAL CIRCUIT |
| If the symptoms still occur after the above area has been inspected and has proven to be normal, replace the ECM. | REMOVAL |