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. |
|
- *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
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- 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.
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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 | .gif) |
GO TO VEHICLE STABILITY CONTROL SYSTEM |
|
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|
2. |
CHECK FOR DTCs (PRE-COLLISION SYSTEM) |
(a) Clear the DTCs.
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(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:
How To Proceed With Troubleshooting
CAUTION / NOTICE / HINT
HINT:
The wireless door lock control system troubleshooting procedure is based
on the premise that the power door lock control system is operating normally.
Check the power door lock control system first before troubleshooting the
wireless door lock cont ...
Definition Of Terms
DEFINITION OF TERMS
Term
Definition
Monitor Description
Description of what the ECM monitors and how it detects malfunctions
(monitoring purpose and details).
Related DTCs
A group of diagnostic trouble codes that are ...
Transfer L4 Position Switch Circuit (C1268)
DESCRIPTION
A-TRAC is activated if wheel skid is detected while the transfer is in the L4
position.
DTC Code
DTC Detecting Condition
Trouble Areas
C1268
L4 detection switch signal input to skid control ECU (master cylinder
solenoid ...
