Dynamic Radar Cruise Control System - Diagnosis System

Lexus IS250 IS220d GSE20 ALE20 - CRUISE CONTROL


DYNAMIC RADAR CRUISE CONTROL SYSTEM - DIAGNOSIS SYSTEM

DIAGNOSIS FUNCTION
Dynamic Radar Cruise Control System - Diagnosis System. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20

The diagnosis function makes the master warning light and the multi-information display come on, and the CRUISE main indicator light blinks as shown in the illustration. When a malfunction occurs in the dynamic radar cruise control system, the DTCs are stored in the ECM.

  • NOTICE:
Dynamic Radar Cruise Control System - Diagnosis System. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20
The master warning light goes off if the system returns to normal condition.
Since the stored data in the ECM is erased by disconnecting the EFI and ETCS fuses or the battery terminal, do not disconnect them until the inspection has been completed.
DESCRIPTION

The ECM controls the dynamic radar cruise control system of the vehicle. The data and DTCs relating to the dynamic radar cruise control system can be read from the DLC3 of the vehicle. If either DTC or CRUISE OK is not displayed on the multi-information display on the combination meter when checking for DTCs, there may be a problem with either the combination meter or the CAN communication and multiplex communication systems. Use the intelligent tester to check and solve the problem.

CHECK DLC3
Dynamic Radar Cruise Control System - Diagnosis System. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20

The vehicle's ECM uses the ISO 15765-4 for communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.

Terminal No. (Symbols)Terminal DescriptionConditionSpecified Condition
J21-7 (SIL) - J21-5 (SG)Bus "+" lineDuring transmissionPulse generation
J21-4 (CG) - Body groundChassis groundAlwaysBelow 1 Ω
J21-5 (SG) - Body groundSignal groundAlwaysBelow 1 Ω
J21-16 (BAT) - Body groundBattery positiveAlways11 to 14 V
J21-6 (CANH) - J21-14 (CANL)HIGH-level CAN bus lineEngine switch off54 to 67 Ω
J21-6 (CANH) - Battery positiveHIGH-level CAN bus lineEngine switch off1 MΩ or higher
J21-6 (CANH) - J21-4 (CG)HIGH-level CAN bus lineEngine switch off3 kΩ or higher
J21-14 (CANL) - Battery positiveLOW-level CAN bus lineEngine switch off1 MΩ or higher
J21-14 (CANL) - J21-4 (CG)LOW-level CAN bus lineEngine switch off3 kΩ or higher

If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.

  • HINT:
  • Connect the cable of the intelligent tester to the DLC3, turn the engine switch on (IG), and attempt to use the tester. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or the tester.
If communication is normal when the tester is connected to another vehicle, inspect the DLC3 on the original vehicle.
If communication is still not possible when the tester is connected to another vehicle, the problem may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.
CHECK INDICATOR
Dynamic Radar Cruise Control System - Diagnosis System. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Turn the engine switch on (IG).

Check that the CRUISE main indicator light and RADAR READY indicator come on when the main switch ON-OFF button is pushed on, and that the indicator light and the indicator go off when the ON-OFF button is pushed off.

  • HINT:
If the indicator check result shows a problem, proceed to troubleshooting for the combination meter section.
Dynamic Radar Cruise Control System - Diagnosis System. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20
If a malfunction occurs in the vehicle speed sensors, the stop light switch, or other related parts during cruise control driving, the ECU actuates AUTO CANCEL of the cruise control and blinks the CRUISE main indicator light. This indicator light informs the driver of the malfunction. At the same time, the malfunction is stored as a diagnostic trouble code.