LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2005 >> RX 330 AWD >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Dynamic Laser Cruise Control System >> Problem Symptoms Table
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Problem Symptoms Table

If a normal code is displayed during the DTC check but the problem still occurs, check the circuits for each problem symptom in the order given in the table below and to the relevant troubleshooting Service Category.

HINT:

Inspect the "Fuse" and "Relay" before confirming the suspected area as shown in the charts below.

Inspect each malfunction circuit in numerical order for the corresponding symptom.

If the malfunction still exist even after checking and confirming that all the circuit are normal, replace the ECM.

Fig 1: Problem Symptoms Chart
G03007885Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
PROBLEM SYMPTOMS TABLE

Symptom Suspect Area Refer To
Main switch cannot be turned ON.
(Cruise indicator light in combination meter does not come on.)
  1. Cruise control switch circuit
  2. Cruise main indicator light circuit
  3. ECM
  1. CRUISE CONTROL SWITCH CIRCUIT 
  2. CRUISE MAIN INDICATOR LIGHT CIRCUIT 
  3. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
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.)
  1. Cruise control switch circuit
  2. ECM
  1. CRUISE CONTROL SWITCH CIRCUIT 
  2. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Setting cannot be done.
(Indicator light in combination meter comes on when the main switch is turned ON and it remains ON while setting.)
  1. Cruise control switch circuit
  2. Stop lamp switch circuit
  3. Park/Neutral position switch circuit
  4. Combination meter system
  5. ECM
  1. CRUISE CONTROL SWITCH CIRCUIT 
  2. DTC P0571/52: BRAKE SWITCH "A" CIRCUIT 
  3. DTC P0705: TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT)
  4. HOW TO PROCEED WITH TROUBLESHOOTING
  5. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
While the vehicle is driving with cruise control, the set control is canceled.
(Indicator light and CRUISE remain ON.)
  1. Cruise control switch circuit
  2. Vehicle speed sensor circuit
  3. Stop lamp switch circuit
  4. Cruise main indicator light circuit
  5. Park/Neutral position switch circuit
  6. ECM
  1. CRUISE CONTROL SWITCH CIRCUIT 
  2. DTC P0500/21: VEHICLE SPEED SENSOR CIRCUIT, DTC P0503/23 VEHICLE SPEED SENSOR "A" INTERMITTENT/ERRATIC/HIGH 
  3. DTC P0571/52: BRAKE SWITCH "A" CIRCUIT 
  4. CRUISE MAIN INDICATOR LIGHT CIRCUIT 
  5. DTC P0705: TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT)
  6. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Hunting
(Speed is not constant.)
  1. Vehicle speed sensor circuit
  2. Malfunction in speedometer circuit
  3. Laser radar sensor circuit
  4. Distance control ECU circuit
  5. ECM
  1. DTC P0500/21: VEHICLE SPEED SENSOR CIRCUIT, DTC P0503/23 VEHICLE SPEED SENSOR "A" INTERMITTENT/ERRATIC/HIGH 
  2. MALFUNCTION IN SPEEDOMETER
  3. DTC P1570/73: LASER RADAR SENSOR MALFUNCTION 
  4. DISTANCE CONTROL ECU POWER SOURCE CIRCUIT 
  5. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Setting cannot be cancelled.
(When Coast, Acceleration, Resume, Set speed change and Control switch are operated.)
  1. Cruise control switch circuit
  2. ECM
  1. CRUISE CONTROL SWITCH CIRCUIT 
  2. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Erroneous detection or lost sight of the vehicle ahead.
  1. Clean laser radar sensor
  2. Improper aiming of laser sensor beam axis
  1. -
  2. ADJUSTMENT
Alarm buzzer does not sound.
  1. Buzzer circuit
  2. VSC system
  3. Laser radar sensor circuit
  4. Distance control ECU
  5. ECM
  1. DTC P1575/66: WARNING BUZZER MALFUNCTION 
  2. HOW TO PROCEED WITH TROUBLESHOOTING
  3. DTC P1570/73: LASER RADAR SENSOR MALFUNCTION 
  4. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
  5. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Set distance cannot be changed.
  1. Combination meter system
  2. Distance control switch
  3. ECM
  1. HOW TO PROCEED WITH TROUBLESHOOTING
  2. DISTANCE CONTROL SWITCH CIRCUIT 
  3. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
No display.
  1. Combination meter system
  2. ECM
  1. HOW TO PROCEED WITH TROUBLESHOOTING
  2. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
No brake control (when decelerating)
  1. ABS solenoid circuit
  2. VSC system
  3. Distance control ECU
  4. ECM
  1. DTC C0278/11, C0279/12: OPEN OR SHORT CIRCUIT IN ABS SOLENOID RELAY, SHORT CIRCUIT IN ABS SOLENOID RELAY CIRCUIT
  2. HOW TO PROCEED WITH TROUBLESHOOTING
  3. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
  4. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Constant speed mode cannot be ON.
  1. Cruise control switch circuit
  2. ECM
  3. Combination meter system
  1. CRUISE CONTROL SWITCH CIRCUIT 
  2. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
  3. HOW TO PROCEED WITH TROUBLESHOOTING
Vehicle speed setting cannot be cancelled with wiper Lo/Hi. (Including automatic wiper)
  1. Rain sensor system
  2. Wiper signal circuit
  3. Distance control ECU
  4. ECM
  1. RAIN SENSOR CIRCUIT
  2. WIPER SIGNAL CIRCUIT 
  3. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
  4. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Setting cannot be cancelled in SNOW mode.
  1. Pattern select switch circuit
  2. Automatic transmission system
  3. ECM
  1. PATTERN SELECT SWITCH CIRCUIT
  2. HOW TO PROCEED WITH TROUBLESHOOTING
  3. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Unable to adjust (complete) the optical axis of the laser radar sensor.
  1. Check for DTC P1570/73
  2. Check the position, distance and angle of the reflector
  3. Check the installation of the laser radar sensor
  4. Laser radar sensor
  5. ECM
  1. PRE-CHECK 
  2. ADJUSTMENT
  3. -
  4. DTC P1570/73: LASER RADAR SENSOR MALFUNCTION 
  5. ELECTRONIC CIRCUIT INSPECTION PROCEDURE
scientia non olet · About LEMON Manuals