Lexus IS250 IS220d GSE20 ALE20 - PARK ASSIST / MONITORING
CLEARANCE SONAR SYSTEM - DIAGNOSIS SYSTEM
| DESCRIPTION |
DIAGNOSTIC SYSTEM
When troubleshooting a vehicle with the diagnosis system, the only difference from the usual troubleshooting procedure is connecting the intelligent tester to the vehicle and reading various data output from the vehicle's clearance warning ECU.
The clearance warning ECU records DTCs when the ECU detects a malfunction in the ECU itself or in its circuits.
To check the DTCs, connect the intelligent tester to the DLC3 on the vehicle. The intelligent tester enables you to erase the DTCs, activate the various actuators, and check the freeze frame data and Data List.
Check the DLC3.
The clearance warning ECU 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.
| Symbols (Terminal No.) | Terminal Description | Condition | Specified Condition |
| SIL (7) - SG (5) | Bus "+" line | During communication | Pulse generation |
| CG (4) - Body ground | Chassis ground | Always | Below 1 Ω |
| SG (5) - Body ground | Signal ground | Always | Below 1 Ω |
| BAT (16) - Body ground | Battery positive | Always | 11 to 14 V |
| CANH (6) - CANL (14) | HIGH-level CAN bus line | Engine switch off | 54 to 67 Ω |
| CANH (6) - Battery positive | HIGH-level CAN bus line | Engine switch off | 1 MΩ or higher |
| CANH (6) - CG (4) | HIGH-level CAN bus line | Engine switch off | 3 kΩ or higher |
| CANL (14) - Battery positive | LOW-level CAN bus line | Engine switch off | 1 MΩ or higher |
| CANL (14) - CG (4) | LOW-level CAN bus line | Engine switch off | 3 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 with the tester.