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.

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

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

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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.

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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

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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:

 Dtc Check / Clear

DTC CHECK / CLEAR CHECK DTC (a) Connect the Techstream to the DLC3. (b) Turn the power switch on (IG). (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Sliding Roof / Trouble Codes. Body Electrical > Sliding Roof > Trouble Codes (e) Check the details of the DTC(s).

 System Diagram

SYSTEM DIAGRAM Communication Table Sender Receiver Signal Line Main Body ECU (Multiplex Network Body ECU) Outer Mirror Control ECU Assembly IG signal ACC signal Outer mirror switch assembly signal Mirror position request signal (memory and reactivation function) Mirror

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