Description Of Functions
- Anti-lock brake system (ABS) Helps prevent wheel lock when the brakes are applied quickly or on a slippery road surface.
- Electronic brake distribution control (EBD) The EBD control uses the ABS to control distribution of brake force to front and rear wheels depending on driving conditions. Also, the system controls application of braking force to right and left wheels to stabilize vehicle motion while cornering.
- Brake assist (BA) The main purpose of brake assist is to provide additional braking force for a driver who cannot depress the brake pedal hard when hard braking is needed. With this assist, braking performance of the vehicle is assured.
- Traction control (TRC) Controls slipping of driving wheels when the driver depress the accelerator pedal too far to starts or accelerates the vehicle on a slippery surface.
- Vehicle stability control Controls vehicle skidding sideways when vehicle is apt to understeer or oversteer excessively while cornering.
- Parts function Parts Function Brake actuator Assembly Skid control ECM Based on signals from sensors and switches, identifies driving conditions and sends brake control signal to the brake actuator Assembly. Master cylinder pressure sensor Detects master cylinder pressure. Pump motor Activates the pump in the brake actuator Assembly. Solenoid valve The hydraulic circuit has two master cylinder cut solenoid valves, two intake solenoid valves, four retaining solenoid valves, and four relief solenoid valves. To control a hydraulic pressure applied to the wheel cylinder, switches the hydraulic circuits based on the signal from the skid control during operation of the brake control system. Yaw rate and acceleration sensors The yaw rate sensor detects the vehicle yaw rate. The acceleration sensor detects longitudinal acceleration and lateral acceleration of the vehicle. Skid control ECM ABS motor relay Provides power supply to the pump motor. ABS solenoid relay Provides power supply to the solenoid valve. Speed sensor Detects four wheels and speed of each wheel. Console switch Assembly Vehicle stability control OFF switch Normal mode, TRC OFF mode, or Vehicle stability control OFF mode is selectable. Vehicle stability control SPORT switch Either normal mode or Vehicle stability control SPORT mode is selectable. Stop light switch Assembly Detects the brake pedal signal issued when the pedal is depressed. Main body ECM (multiplex network body ECM) Sends parking brake switch signal to the skid control ECM. Parking brake switch Assembly Detect the condition of the parking brake pedal. ECM Sends signals including the accelerator pedal opening angle signal and the engine speed signal to the skid control ECM. Controls the engine output based on the signal received from the skid control ECM. TCM Sends gear position signal to the skid control ECM. Steering angle sensor Detects the steering direction of a steering wheel and the steering wheel angle. Parts Function Combination meter Assembly ABS warning light When the skid control ECM detects an ABS malfunction, it illuminates to let the driver know the malfunction occurrence. Brake warning light When the skid control ECM detects an EBD malfunction or a brake system malfunction, it illuminates to let the driver know the malfunction occurrence. When the brake fluid level is low, it illuminates to let the driver know the condition. When the parking brake is operated, it illuminates to let the driver know the operation. TRC OFF indicator light When the TRC OFF mode is selected, it illuminates to let the driver know the selection. Vehicle stability control OFF indicator light V When the Vehicle stability control OFF mode or Vehicle stability control SPORT mode is selected, it illuminates to inform the driver of the selection. Vehicle stability control SPORT indicator light When the stability control SPORT mode is selected, it illuminates to inform the driver of the selection. Slip indicator light When TRC control or Vehicle stability control is taking place, it flashes to inform the driver that the control is active. When the skid control ECM detects a TRC malfunction and/or a Vehicle stability control malfunction, it illuminates to inform the driver of the malfunction occurrence.
When an EFI system error is input, this code will be output to illuminate the slip indicator light. (Vehicle stability control system is normal.)
Under the EFI system error, TRC and Vehicle stability controls are prohibited for fail safe.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1201 | When receiving engine error signal while driving. | Engine control computer |
Each solenoid adjusts the pressure applied to each wheel cylinder to control the vehicle.
While an abnormal diagnostic code is being output, the fail safe function turns OFF the solenoid relay forcibly. Therefore the solenoid will not be turned ON.
The solenoid relay and the solenoid are integrated into the brake actuator Assembly.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1225 C1226 C1227 C1228 C1468 C1469 C146A C146B | When the solenoid signal does not match the check result | Brake actuator Assembly (Internal error) |
| Diagnostic codes | Relevant solenoid |
|---|---|
| C1225 | [VDC Switchover Valve (P)] |
| C1226 | [VDC Switchover Valve (S)] |
| C1227 | [VDC change-over valve 2 (P)] |
| C1228 | [VDC change-over valve 2 (S)] |
| C1468 | [FR Valve] |
| C1469 | [FL Valve] |
| C146A | [RR Valve] |
| C146B | [RL Valve] |
The skid control computer (brake actuator Assembly) inputs the steering sensor signal through CAN communication.
If there is a trouble in the communication line connected to the steering sensor, the diagnostic code "U0126(Nonarrival of H-CAN data(Steering angle sensor))" is output.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1231 | When the voltage at +BS terminal is between 9.6 to 16.5 V, a steering sensor error signal is received. | ECM IG1 fuse Wiring harness or connector Steering sensor |
Scheme 27
If there is a malfunction in the yaw rate sensor which is integrated into the skid control computer (brake actuator Assembly), the skid control computer (brake actuator Assembly) outputs a diagnostic code and prohibits the Vehicle stability control operation for fail safe.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1234 | Skid control computer (brake actuator Assembly) internal error (yaw rate sensor) | Skid control computer (brake actuator Assembly) |
| C1419 | Skid control computer (brake actuator Assembly) internal error (G sensor) | |
| C1472 | Skid control computer (brake actuator Assembly) internal error (lateral G sensor) | |
| C1474 | Skid control computer (brake actuator Assembly) internal error (longitudinal G sensor) |
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1237 | Outputs from the speed sensors at 4 wheels are all different. Speed sensor signal pulse error for 3 wheels or more. ABS control continues for long time Vehicle stability control continues for long time | Tire size error Speed sensor Speed sensor rotor Wiring harness or connector Skid control computer (brake actuator Assembly) |
If there is a malfunction in the power supply circuit, the skid control computer (brake actuator Assembly) outputs a diagnostic code and prohibits the operation by fail safe function.
If the voltage to the +BS terminal is not within the range of DTC detecting conditions due to a malfunctioning power supply or charging circuit (including battery and alternator circuits), this code will be stored in memory.
When the voltage to the +BS terminal returns to normal, this diagnostic code will be cleared.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1241 | The voltage applied to the +BS terminal continues 9.6V or less for 1 second or more, at the vehicle speed of 6 km/h or more. The voltage applied to the +BS terminal continues 6.9 V or less for 1 second or more, at the vehicle speed of 6 km/h or more. When the voltage of the +BS terminal is 9.6 V or more at the vehicle speed of 15 km/h or more and the skid control computer (brake actuator Assembly) starts the solenoid, the voltage of the solenoid relay has dropped significantly. | ABS No. 2 fuse ECM IG1 fuse Battery Charging system Wiring harness or connector Skid control computer (brake actuator Assembly) |
Scheme 28
The master cylinder's pressure sensor is integrated into the brake actuator Assembly and connected to the skid control computer.
Scheme 29
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1246 | Voltage of the sensor signal is outside the specified range. The offset value of the sensor signal is outside the specified range. | STOP fuse Stop light switch circuit Wiring harness and connector Brake actuator Assembly (master cylinder pressure sensor circuit) Skid control computer (brake actuator Assembly) |
The skid control computer (brake actuator Assembly) inputs the stop light switch signal to input the brake operation conditions. When the skid control computer (brake actuator Assembly) judges one of the followings, this diagnostic code will be stored in memory.
- Stop light switch ON/OFF, stuck
- Accelerator pedal and brake pedal, depressed simultaneously (*)
Note. *: If the accelerator pedal and the brake pedal are depressed simultaneously, the skid control computer (brake actuator Assembly) judges that the stop light switch is stuck to ON and the diagnostic code may be stored in memory. However, this is not a malfunction.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1249 | The accelerator pedal has been ON and the brake has been OFF, at the vehicle speed of 10km/h or more. When the pressure inside the master cylinder increases with the stop light switch OFF. | STOP fuse Stop light switch Assembly Noise filter Wiring harness and connector Skid control computer (brake actuator Assembly) |
Scheme 30
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1288 | The engine variation information which is stored in the skid control computer (brake actuator Assembly) and the engine control computer's variations do not match. | Engine control computer Skid control computer (brake actuator Assembly) |
When an automatic transmission system error is input, this code will be output to illuminate the slip indicator light. (VSC system is normal)
Under the automatic transmission system error, TRC and Vehicle stability controls are prohibited for fail safe.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1294 | Transmission error signal is received | Transmission control computer |
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1300 | ECM internal error | Skid control computer (brake actuator Assembly) |
The speed sensor detects the wheel speed and sends the signal to the skid control computer (brake actuator Assembly). These signals are used for ABS control.
The speed sensor detects magnetic field changes in the magnetic rotor, where the N and S poles are evenly allocated in a circumferential direction, and generates a vehicle speed pulse.
With this vehicle speed pulse, the skid control computer (brake actuator Assembly) detects each wheel's speed.
Note. The following voltage outputs are the values when the vehicle harness connectors are connected to the skid control computer (brake actuator Assembly) and the speed sensor.
Scheme 31
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1330 C1331 | Speed sensor's power supply or signal line is shorted. | Front speed sensor Wiring harness or connector Skid control computer (brake actuator Assembly) |
| C1464 C1465 | Signal values are outside the specified range when signals of the four speed sensors are compared. An abnormal wheel speed is detected. | Front speed sensor Front speed sensor, poor installation Wiring harness or connector Speed sensor rotor Skid control computer (brake actuator Assembly) |
Scheme 32
The speed sensor detects the wheel speed and sends the signal to the skid control computer. These signals are used for ABS control.
The speed sensor detects magnetic field changes in the magnetic rotor, where the N and S poles are evenly allocated in a circumferential direction, and generates a vehicle speed pulse.
With this vehicle speed pulse, the skid control computer detects each wheel's speed.
Note. The following voltage outputs are the values when the vehicle harness connectors are connected to the skid control computer (brake actuator Assembly) and the speed sensor.
Scheme 33
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C1332 C1333 | Speed sensor's power supply or signal line is shorted. | Rear speed sensor Wiring harness or connector Skid control computer (brake actuator Assembly) |
| C1466 C1467 | Signal values are outside the specified range when signals of the four speed sensors are compared. An abnormal wheel speed is detected. | Rear speed sensor Rear speed sensor, poor installation Wiring harness or connector Speed sensor rotor Skid control computer (brake actuator Assembly) |
Scheme 34
The ABS motor relay is integrated into the brake actuator Assembly.
The skid control computer (brake actuator Assembly) turns on the ABS motor relay to operate the pump motor in the brake actuator Assembly while ABS, TRC, Vehicle stability control, or brake assist is operating.
If the power supply voltage for the ABS motor relay drops due to the battery or alternator's insufficient output, this code may be stored in memory.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C146C | When the motor relay is started, power is not supplied to the pump motor. When the motor relay is not operating, voltage inside the pump motor increases. Skid control computer (brake actuator Assembly) detects improper operation of the pump motor. | ABS No. 2 fuse Wiring harness or connector Skid control computer (brake actuator Assembly) |
Scheme 35
The ABS solenoid relay is integrated into the brake actuator Assembly and supply power to the ABS solenoid.
After turning IG ON, if the solenoid has been judged as normal by self-diagnosis during initial check, turn the relay ON. If open or short circuit has been detected, turn the relay OFF.
If the power supply voltage for the ABS solenoid relay drops due to the battery or alternator's insufficient output, this code may be stored in memory.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| C146E | The ABS solenoid relay driving circuit in the skid control computer (brake actuator Assembly) does not operate normally. The ABS solenoid relay cannot be turned ON/OFF. | ABS No. 2 fuse Wiring harness or connector Skid control computer (brake actuator Assembly) |
Scheme 36
The skid control computer (brake actuator Assembly) inputs signals of the engine control computer, the transmission control computer, and the steering sensor through CAN communication.
| Diagnostic codes | DTC detecting conditions | Faulty part |
|---|---|---|
| U0073 | The voltage at +BS terminal is between 9.6 to 16.5 V and bus off status continues for 0.1 second or more. | CAN communication system |
| U0100 | The vehicle is running and the voltage at +BS terminal is between 9.6 to 16.5 V, and the data transmission or reception to the engine control computer is impossible for 0.5 seconds or more. | CAN communication line Skid control computer (brake actuator Assembly) Engine control computer |
| U0101 | The vehicle is running and the voltage at +BS terminal is between 9.6 to 16.5 V, and the data transmission or reception to the transmission control computer is impossible for 0.5 seconds or more. | CAN communication line Skid control computer (brake actuator Assembly) Transmission control computer |
| U0126 | The vehicle is running and the voltage at +BS terminal is between 9.6 to 16.5 V, and the data reception from the steering sensor is impossible for 0.1 second or more. | CAN communication line Skid control computer (brake actuator Assembly) Steering sensor |
The skid control ECM is connected to the combination meter Assembly through the CAN communication.
When one of the following conditions is detected, the ABS warning light illuminates.
- The skid control ECM connector is disconnected from the skid control ECM.
- The skid control ECM has trouble in its internal circuit.
- Wiring harness between the combination meter Assembly and the skid control ECM are open.
- ABS control system is defective.
Note. When the skid control ECM has trouble, in some cases the SSM3 may not be useful.
Scheme 37
The skid control ECM is connected to the combination meter Assembly through the CAN communication.
The skid control ECM is connected to the combination meter Assembly through the CAN communication.
When one of the following conditions is detected, the brake warning light illuminates.
- The skid control ECM connector is disconnected from the skid control ECM.
- The brake fluid level is insufficient.
- The parking brake is being applied.
- EBD control is not allowed.
Scheme 38
The skid control ECM is connected to the combination meter Assembly through the CAN communication.
The skid control ECM is connected to the combination meter Assembly through the CAN communication. When the Vehicle stability control OFF switch is pressed, TRC is turned to OFF. When this switch is kept pressed, TRC and Vehicle stability control are turned to OFF. When TRC switches to OFF, the TRC OFF indicator light illuminates.
Scheme 39
The skid control ECM is connected to the combination meter Assembly through the CAN communication. When the Vehicle stability control OFF switch is pressed, TRC is turned to OFF. When this switch is kept pressed, TRC and Vehicle stability control are turned to OFF. When TRC switches to OFF, the TRC OFF indicator light illuminates.
The skid control ECM is connected to the combination meter Assembly through the CAN communication. The system is switched between Normal mode and SPORT mode each time Vehicle stability control SPORT switch is pressed. When Vehicle stability control SPORT switch is pressed in SPORT mode, the system switches to Normal mode.
The skid control ECM is connected to the combination meter Assembly through the CAN communication. When Vehicle stability control and/or TRC is active, the slip indicator light flashes. When a malfunction is detected, the slip indicator light illuminates and the driver is warned of the condition.
Scheme 40
The skid control ECM is connected to the combination meter Assembly through the CAN communication.
See also:
• CHECKING/CLEARING DTC