DESCRIPTION If a
malfunction is detected in the power supply circuit, the skid control
ECU (brake actuator assembly) stores this DTC and the fail-safe function
prohibits ABS operation. This DTC is stored when the +BS terminal
voltage meets one of the DTC detection conditions due to a malfunction
in the power supply or charging circuit such as the battery or
alternator circuit, etc. The DTC is cleared when the +BS terminal
voltage returns to normal. |
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area | |
C1241 | Low or High Power Supply Voltage |
Any of the following is detected:
- The vehicle speed is 6 km/h (4 mph) or more and the +BS terminal voltage
(soft low voltage) is less than 9.6 V for 1 second or more.
- The vehicle speed is 6 km/h (4 mph) or more and the +BS terminal voltage
(hard low voltage) is less than 6.9 V for 1 second or more.
- The vehicle speed is 15 km/h (9 mph) or more, the +BS terminal voltage
is 9.6 V or more, the skid control ECU (brake actuator assembly) turns
on more than one valve at the same time within a short period of time
and the valve relay supply voltage drop exceeds the threshold.*
- The +BS terminal voltage is less than 6.7 V and the skid control ECU
(brake actuator assembly) judges that power supply voltage is abnormal
for 0.06 seconds or more.
|
- ABS NO. 2 fuse
- Battery
- Charging system
- Power source circuit
- Ground circuit
- Internal power supply circuit of the skid control ECU (brake actuator assembly)
| *:
The skid control ECU (brake actuator assembly) monitors the resistance
of the power source line at the +BS terminal. A malfunction is detected
when an abnormality occurs in the +BS terminal wire harness or its
connection and the skid control ECU (brake actuator assembly) determines
that the wiring resistance at the +BS terminal exceeds the standard
resistance. DTC Detection Conditions: C1241 | |
Vehicle Condition | |
Pattern 1 | Pattern 2 |
Pattern 3 | Pattern 4 | |
Diagnosis Condition | The vehicle speed is 6 km/h (4 mph) or more. |
○ | ○ |
- | - | |
The vehicle speed is 15 km/h (9 mph) or more and the +BS terminal voltage is 9.6 V or more. |
- | - |
○ | - | |
The +BS terminal voltage is less than 6.7 V. |
- | - |
- | ○ | |
Malfunction Status | The +BS terminal voltage (soft low voltage) is less than 9.6 V. |
○ | - |
- | - | |
The +BS terminal voltage (hard low voltage) is less than 6.9 V. |
- | ○ |
- | - | |
The
skid control ECU (brake actuator assembly) turns on more than one valve
at the same time within a short period of time and the valve relay
supply voltage drop exceeds the threshold.* |
- | - |
○ | - | |
The skid control ECU (brake actuator assembly) judges that power supply voltage is abnormal. |
- | - |
- | ○ | |
Detection Time | 1 second or more |
1 second or more | - |
0.06 seconds or more | |
Number of Trips | 1 trip |
1 trip | 1 trip |
1 trip | *:
The skid control ECU (brake actuator assembly) monitors the resistance
of the power source line at the +BS terminal. A malfunction is detected
when an abnormality occurs in the +BS terminal wire harness or its
connection and the skid control ECU (brake actuator assembly) determines
that the wiring resistance at the +BS terminal exceeds the standard
resistance. HINT: DTC will be output when conditions for either of the patterns in the table above are met. WIRING DIAGRAM
 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 (a) Check the battery voltage.
Standard Voltage: |
Tester Connection | Condition |
Specified Condition | |
Positive (+) terminal - Negative (-) terminal |
Engine switch off | 11 to 14 V |
| NG |
 | CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY |
|
OK |
 | |
| 2. |
CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL) |
| (a) Make sure that there is no looseness at the locking part and the connecting part of the connector.
OK: The connector is securely connected. |
 |
|
*a | Front view of wire harness connector
(to Skid Control ECU (Brake Actuator Assembly)) | | |
(b) Disconnect the A28 skid control ECU (brake actuator assembly) connector.
(c) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (d) Measure the voltage according to the value(s) in the table below.
Standard Voltage: |
Tester Connection | Condition |
Specified Condition | |
A28-30 (+BS) - Body ground |
Always | 11 to 14 V | |
A28-36 (IG1) - Body ground |
Engine switch on (IG) |
11 to 14 V |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) |
|
OK | |
| |
| 3. |
CHECK HARNESS AND CONNECTOR (GND1 TERMINAL) |
| (a) Turn the engine switch off. |
 |
|
*a | Front view of wire harness connector
(to Skid Control ECU (Brake Actuator Assembly)) | | |
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance: |
Tester Connection | Condition |
Specified Condition | |
A28-46 (GND1) - Body ground |
Always | Below 1 Ω |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT) |
|
OK | |
| |
(a) Reconnect the A28 skid control ECU (brake actuator assembly) connector.
(b) Clear the DTCs. Chassis > ABS/VSC/TRAC/EPB > Clear DTCs (c) Turn the engine switch off.
(d) Start the engine. (e) Perform a road test. (f) Check if the same DTC is output. Chassis > ABS/VSC/TRAC/EPB > Trouble Codes
|
Result | Proceed to | |
C1241 is not output | A | |
C1241 is output | B |
| A |
| USE SIMULATION METHOD TO CHECK |
| B |
| REPLACE BRAKE ACTUATOR ASSEMBLY | | 
