Lexus ES manuals

Lexus ES: Stop Light Relay Circuit (C1A4B)

DESCRIPTION

When a stop light relay circuit malfunction signal sent from the electronically controlled brake system is detected by the clearance warning ECU assembly, DTC C1A4B is stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A4B

Stop Light Relay Circuit

Stop light relay circuit malfunction

Electronically controlled brake system

CAUTION / NOTICE / HINT

NOTICE:

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

    Click here

  • After replacing an ultrasonic sensor or the clearance warning ECU assembly, perform the necessary procedures (adjustment, calibration, initialization or registration).

    Click here

  • When DTC C1A4B is stored, there may be a malfunction in the lighting system. Inspect the lighting system before performing the following procedure.

    Click here

PROCEDURE

1.

CHECK DTC OUTPUT

(a) Using the Techstream, check for DTCs according to the prompts on the screen.

HINT:

After turning the power switch from off to on (IG), wait 4 seconds or more before checking for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

(b) Clear the DTCs according to the screen on the Techstream.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(c) Recheck for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

HINT:

  • DTC C1A4B is stored when a malfunction signal sent from the electronically controlled brake system is detected.
  • If the malfunctioning part has been repaired or replaced before rechecking for DTCs, DTC C1A4B will not be output again.
  • If DTC C1A4B is output frequently, duplicate the conditions that cause the problem symptoms and perform troubleshooting again, even though the DTC was not output when rechecking for DTCs.

    Click here

Result

Proceed to

DTC C1A4B is output

A

DTC C1A4B is not output

B

A

GO TO PRE-COLLISION SYSTEM

B

USE SIMULATION METHOD TO CHECK

READ NEXT:

 ENG / EHV Device (C1A40)

DESCRIPTION When a SFI system malfunction signal sent by the hybrid vehicle control ECU is detected by the clearance warning ECU assembly, DTC C1A40 is stored. DTC No. Detection Item DTC Detect

 ENG / EHV Device (C1A40)

DESCRIPTION When a SFI system malfunction signal sent by the hybrid vehicle control ECU is detected by the clearance warning ECU assembly, DTC C1A40 is stored. DTC No. Detection Item DTC Detect

 Brake System (C1A50)

DESCRIPTION When an electronically controlled brake system malfunction signal sent from the skid control ECU is detected by the clearance warning ECU assembly, DTC C1A50 is stored. DTC No. Detect

SEE MORE:

 Throttle/Pedal Position Sensor/Switch "A"/"B" Voltage Correlation Signal Cross Coupled (P21352B)

DESCRIPTION Refer to DTC P012011. Click here DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory Note P21352B Throttle/Pedal Position Sensor/Switch "A"/"B" Voltage Correlation Signal Cross Coupled The difference between the output voltage of VTA1 and VTA2

 Components

COMPONENTS ILLUSTRATION *A w/o Headup Display *B w/ Headup Display *1 COWL SIDE TRIM BOARD LH *2 FRONT DOOR OPENING TRIM COVER LH *3 FRONT DOOR SCUFF PLATE LH *4 HAZARD WARNING SIGNAL SWITCH ASSEMBLY *5 INSTRUMENT CLUSTER FINISH PANEL SUB-ASSEMBLY *6 INSTRUMEN

© 2016-2026 Copyright www.lexguide.net