Cruise Control System - Diagnosis System

Lexus IS250 IS220d GSE20 ALE20 - CRUISE CONTROL


CRUISE CONTROL SYSTEM - DIAGNOSIS SYSTEM

DESCRIPTION

The ECU controls the cruise control system of the vehicle. The data and DTCs relating to the 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.

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 ISO 15031-03 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
  • 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 with either 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
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 illuminates when the cruise control main switch is turned on, and that the indicator light turns off when the main switch is turned off. If the results are not as specified, inspect the CRUISE main indicator light circuit .

  • HINT:
Cruise Control System - Diagnosis System. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20
  • While driving with cruise control, the ECM activates AUTO CANCEL of the cruise control system when a malfunction occurs in one of the following: vehicle speed sensors, stop light switch, or other related parts. When AUTO CANCEL is activated, the CRUISE main indicator light outputs the blinking pattern shown to the left. At the same time, data of the malfunction is stored as a DTC.