Malfunction in Deceleration Sensor (C1420)
DESCRIPTION
This DTC is
stored when the skid control ECU (brake actuator assembly) detects an
abnormality in the difference between the acceleration sensor value and
the control value estimated based on the yaw rate sensor, steering angle
sensor and speed sensor signals.
The airbag sensor assembly has a built-in yaw rate and acceleration sensor and detects the vehicle condition.
|
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area |
|
C1420 | Malfunction in Deceleration Sensor |
The
difference between the acceleration sensor value and the control value
estimated inside the skid control ECU (brake actuator assembly) is
abnormal. |
- Acceleration sensor (airbag sensor assembly) installation
- Acceleration sensor (airbag sensor assembly)
|
CAUTION / NOTICE / HINT
NOTICE:
After
replacing or reinstalling the yaw rate and acceleration sensor (airbag
sensor assembly), perform system variant learning and acceleration
sensor zero point calibration.
Click here 
PROCEDURE
| 1. |
CHECK AIRBAG SENSOR ASSEMBLY INSTALLATION |
(a) Check that the yaw rate and acceleration sensor (airbag sensor assembly) has been installed properly.
Click here
OK:
The yaw rate and acceleration sensor (airbag sensor assembly) is tightened to the specified torque.
The yaw rate and acceleration sensor (airbag sensor assembly) is not installed in a tilted position.
| OK |
 | REPLACE AIRBAG SENSOR ASSEMBLY |
| NG |
| INSTALL AIRBAG SENSOR ASSEMBLY CORRECTLY |
Open in Stop Light Switch Circuit (C1425)
DESCRIPTION
The skid
control ECU (brake actuator assembly) receives stop light switch
assembly signals and uses them to determine whether or not the brakes
are applied.
The skid control ECU (brake
actuator assembly) has a detection circuit that it uses to detect an
open in the stop light input line.
If the skid control ECU (brake actuator assembly) detects an open in this circuit, it will store this DTC.
|
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area |
|
C1425 | Open in Stop Light Switch Circuit |
An open in the stop light switch assembly input line continues for 3 seconds or more. |
- Wire harness or connector
- Stop light switch assembly
- Skid control ECU (brake actuator assembly)
|
WIRING DIAGRAM
Ref to DTC C1249.
Click here 
CAUTION / NOTICE / HINT
NOTICE:
- When replacing the skid control ECU (brake actuator assembly), perform
system variant learning and acceleration sensor zero point calibration.
Click here
- Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
|
1. | READ VALUE USING TECHSTREAM (BS1 VOLTAGE VALUE) |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.
Chassis > ABS/VSC/TRAC/EPB > Data List
|
Tester Display | Measurement Item |
Range | Normal Condition |
Diagnostic Note |
|
BS1 Voltage Value | +BS voltage value |
Min.: 0.00 V, Max.: 20.00 V |
- | Changes in proportion to battery voltage |
Chassis > ABS/VSC/TRAC/EPB > Data List
|
Tester Display |
| BS1 Voltage Value |
(d) Take a note of the +BS voltage value.
HINT:
The noted +BS voltage value is used in a later step.
|
NEXT |
 | |
| 2. |
INSPECT STOP LIGHT SWITCH ASSEMBLY |
(a) Inspect the stop light switch assembly.
Click here
OK:
The stop light switch assembly is normal.
| NG |
 | REPLACE STOP LIGHT SWITCH ASSEMBLY |
|
OK | |
| |
| 3. |
READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY) |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.
Chassis > ABS/VSC/TRAC/EPB > Data List
|
Tester Display | Measurement Item |
Range | Normal Condition |
Diagnostic Note |
|
Stop Light SW | Stop light switch assembly |
ON or OFF | ON: Brake pedal depressed
OFF: Brake pedal released |
- |
Chassis > ABS/VSC/TRAC/EPB > Data List
|
Tester Display |
| Stop Light SW |
(d) Check that the stop light switch assembly display observed on the Techstream changes according to brake pedal operation.
OK:
The Techstream displays on or off according to brake pedal operation.
| NG |
| GO TO STEP 5 |
|
OK | |
| |
(a) Clear the DTCs.
Chassis > ABS/VSC/TRAC/EPB > Clear DTCs
(b) Turn the engine switch off.
(c) Start the engine.
(d) Depress the brake pedal several times to test the stop light circuit.
(e) Check if the same DTC is output.
Chassis > ABS/VSC/TRAC/EPB > Trouble Codes
|
Result | Proceed to |
|
C1425 is not output | A |
|
C1425 is output | B |
| A |
| USE SIMULATION METHOD TO CHECK |
| B |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| 5. |
CHECK HARNESS AND CONNECTOR (STP TERMINAL) |
| (a) Turn the engine switch off. |
 |
|
*a | Front view of wire harness connector
(to Skid Control ECU (Brake Actuator Assembly)) | | |
(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.
OK:
The connector is securely connected.
(c) Disconnect the A28 skid control ECU (brake actuator assembly) connector.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK:
No deformation or corrosion.
(e) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection | Condition |
Specified Condition |
|
A28-42 (STP) - Body ground |
Stop light switch assembly on (Brake pedal depressed) |
(+BS x 0.85) to 14 V* |
|
A28-42 (STP) - Body ground |
Stop light switch assembly off (Brake pedal released) |
Below 1.5 V |
HINT:
*:
The minimum voltage value varies depending on the +BS terminal voltage
value. The minimum voltage is 85% or more of the +BS terminal voltage.
| OK |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) |
