Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: Stop Light Relay Circuit (C1A4B)

DESCRIPTION

The skid control ECU (master cylinder solenoid)*1 or skid control ECU (brake actuator assembly)*2 sends a stop light operation request signal to the stop light relay (stop light switch assembly). If the skid control ECU (master cylinder solenoid)*1 or skid control ECU (brake actuator assembly)*2 detects a malfunction in the stop light relay circuit, the millimeter wave radar sensor assembly stores DTC C1A4B.

  • *1: for Hydraulic Brake Booster
  • *2: for Vacuum Brake Booster

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A4B

Stop Light Relay Circuit

While the ignition switch is ON, the millimeter wave radar sensor assembly receives a stop light relay circuit malfunction signal from the skid control ECU (master cylinder solenoid)*1 or skid control ECU (brake actuator assembly)*2 for 1 second or more.

  • Vehicle stability control system
  • Millimeter wave radar sensor assembly
  • *1: for Hydraulic Brake Booster
  • *2: for Vacuum Brake Booster

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle. As a result, a DTC may be stored.
  • If the millimeter wave radar sensor assembly has been replaced, be sure to perform millimeter wave radar sensor assembly adjustment.

    Click here

  • The pre-collision system uses the CAN communication system. First, confirm that there are no malfunctions in the CAN communication system. Refer to How to Proceed with Troubleshooting.

    Click here

PROCEDURE

1.

CHECK FOR DTCs (VEHICLE STABILITY CONTROL SYSTEM)

HINT:

Pre-collision system DTC C1A4B may be stored due to a malfunction in the vehicle stability control system. Therefore, it is necessary to check for and troubleshoot vehicle stability control system DTCs first.

(a) Check for DTCs.

Click here

Result

Proceed to

Vehicle stability control system DTCs are not output

A

Vehicle stability control system DTCs are output

B

B

GO TO VEHICLE STABILITY CONTROL SYSTEM

A

2.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here (b) Make sure that the DTC detection conditions are met.

(b) Make sure that the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

(c) Check for DTCs.

Click here

Result

Proceed to

DTC C1A4B is not output

A

DTC C1A4B is output

B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

Skid Control Buzzer Circuit (C1A4A)
DESCRIPTION The millimeter wave radar sensor assembly is connected to the forward recognition camera via CAN communication. The millimeter wave radar sensor assembly operates the pre-collision ala ...

Steering Angle Sensor (C1A47)
DESCRIPTION The millimeter wave radar sensor assembly receives steering angle information from the steering angle sensor (spiral cable with sensor sub-assembly). If the millimeter wave radar sens ...

Other materials:

Illumination Circuit
DESCRIPTION Power is supplied to the radio and display receiver assembly and steering pad switch assembly illumination when the light control switch is in the TAIL or HEAD position. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: The vehicle is equipped with a Supplemental Restrain ...

Dtc Check / Clear
DTC CHECK / CLEAR CHECK DTC (a) Connect the Techstream to the DLC3. (b) Turn the ignition switch to ON. (c) Turn the Techstream on. (d) Enter the following menus: Powertrain / Radar Cruise 1*1 / Trouble Codes. (e) Enter the following menus: Powertrain / Radar Cruise 2*2 / Trouble Codes. (f) C ...

Black Screen
PROCEDURE 1. CHECK DISPLAY SETTING (a) Check that the display is not in "Screen Off" mode. OK: The display setting is not in "Screen Off" mode. NG CHANGE SCREEN TO SCREEN ON MODE OK ...

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