LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2021 >> LS 500 Base, AWD >> Repair and Diagnosis >> Steering >> Steering Control Systems >> Dynamic Rear Steering System - Diagnostic Codes & Symptom Tests >> Dynamic Rear Steering System >> DTC C1B21: ECU Malfunction(CPU); DTC C1B22: ECU Malfunction(Internal Line); DTC C1B23: ECU Malfunction(Substrate Temperature Sensor); DTC C1B25: ECU Malfunction(Flash Memory) [12/2017 - 10/2023] >> Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC C1B21: ECU Malfunction(CPU); DTC C1B22: ECU Malfunction(Internal Line); DTC C1B23: ECU Malfunction(Substrate Temperature Sensor); DTC C1B25: ECU Malfunction(Flash Memory) [12/2017 - 10/2023]: Description

When the DRS ECU (rear steering control ECU) detects an internal problem with the ECU, DTCs are stored.

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Return-to-normal Condition
C1B21 ECU Malfunction(CPU) After the engine switch is turned on (IG), an internal problem with the ECU is detected. DRS ECU (rear steering control ECU) Comes on Engine switch on (IG) again
C1B22 ECU Malfunction(Internal Line) After the engine switch is turned on (IG), an internal problem with the ECU is detected. DRS ECU (rear steering control ECU) Comes on Engine switch on (IG) again
C1B23 ECU Malfunction(Substrate Temperature Sensor) After the engine switch is turned on (IG), an internal problem with the ECU is detected. DRS ECU (rear steering control ECU) Comes on Engine switch on (IG) again
C1B25 ECU Malfunction(Flash Memory) After the engine switch is turned on (IG), an internal problem with the ECU is detected. DRS ECU (rear steering control ECU) Comes on Engine switch on (IG) again