Scheme 1
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Scheme 11
Scheme 12
- WHEN USING JACK OR LIFT When work is performed under the vehicle or when jacking the vehicle up, make sure to turn the engine switch off. If the vehicle must be raised with its engine running, connect terminals 11 (OPA) and 4 (CG) of the DLC3 to stop the vehicle height control operation of the suspension control ECU.
- WHEN ADDING AIR NOTE: Only operate the height control compressor to add air for less than 3 minutes. In order to protect the height control compressor, if it is operated for 3 minutes continuously, its operation is prohibited for 10 minutes. If the height control compressor is operated continuously, its operation is automatically stopped after 3 minutes and its operation is prohibited for 10 minutes to protect the height control compressor.
- DISCONNECT AND CONNECT HEIGHT CONTROL TUBE (Type 1) NOTE: Disconnecting and connecting the height control tube should be performed by hand to prevent dust or foreign objects from entering it. Be careful not to damage the height control tube. Disconnect the height control tube. for Except Front Pneumatic Cylinder: Pinch "A" to disconnect the No. 1 connector and pull it out from the housing. for Front Pneumatic Cylinder: Pinch "B" to disconnect the holder air connector clip and pull it out from the No. 1 connector. Pinch "C" to disconnect the No. 1 connector and pull it out from the housing. Set SST to the tube. SST 09730-00010 Insert SST into the housing to expand the claw of the plug or tube connector in the housing. Pull out the tube with SST inserted. NOTE: Do not force the tube. Insert a screwdriver into the circular hole on the housing, and remove the No. 2 connector, 2 O-rings and plate from the housing. HINT: The O-rings, plate and No. 2 connector are non-reusable parts. Install 2 new O-rings and a new plate. NOTE: When replacing the parts onto which the tube is to be installed with new ones, it is not necessary to perform this installation procedure. Apply MP grease to 2 new O-rings and a new plate, and then install them to a straight tube. NOTE: Install the plate between the O-rings. Air leaks may occur if dust or foreign objects come into contact with the O-rings. Insert the tube onto which the 2 O-rings and plate are installed into the housing, and then lightly push them in with a piece of rolled up cardboard or equivalent. Push the No. 2 connector into the housing until a clicking sound is heard. Install the height control tube. Push the tube and No. 1 connector to the housing until a clicking sound is heard. NOTE: Turn the claw of the connector 90° so that the claw is aligned with the housing port as shown in the illustration. Lightly pull on the tube to make sure that it is securely connected.
- DISCONNECT AND CONNECT HEIGHT CONTROL TUBE (Type 2) NOTE: Disconnecting and connecting the height control tube should be performed by hand to prevent dust or foreign objects from entering it. Be careful not to damage the height control tube. Disconnect the height control tube. Remove the holder. Spread the clip and slowly pull the height control tube straight out. NOTE: Do not completely remove the clip except when replacing it. Remove the 2 O-rings. HINT: Some tubes are equipped with only one O-ring. Install the height control tube. If replacing the clip: Hook one side of the new clip around the union groove, and slide the other side into the opposite side of the union groove. If not replacing the clip: Install 2 new O-rings to the height control tube and coat them with MP grease No. 2. NOTE: Air leaks may occur if dust or foreign objects come into contact with the O-rings. HINT: Some tubes are equipped with only one O-ring. Securely connect the height control tube straight onto the connector until a clicking sound can be heard. NOTE: Connect the height control tube straight in order to prevent air leaks. Install the height control tube to the holder being careful not to apply excessive force to the clip.
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- ADJUST STANDARD VEHICLE HEIGHT Adjust the pressure of the tires. Stabilize the suspension by releasing the parking brake and bouncing the corners of the vehicle up and down. Move the shift lever to N and move the vehicle forward and rearward. Turn the engine switch off. Connect the Techstream to the DLC3. Start the engine. Turn the Techstream on. Enter the following menus: Chassis/Air suspension/Data List. Press the height control switch and adjust the vehicle height to "HEIGHT HIGH". Press the height control switch and return the vehicle height to normal. Using the Data List, confirm that the vehicle height control operation is complete.
- INSPECT VEHICLE HEIGHT Inspect the vehicle height (see «ADJUSTMENT» ). NOTE: The possible vehicle height automatic adjustment value is 20 mm. If the "Height Adjust value + (Standard value - Measurement value - After Height Adjust value)" is 20 mm or more, first perform the standard vehicle height adjustment (height control link adjustment)
- ADJUST HEIGHT CONTROL SENSOR LINK SUB-ASSEMBLY (for Front) NOTE: First adjust the height control sensor link that has the highest deviation from the standard value. If the deviation of the front and rear link is the same, adjust the front link first. Loosen the 2 lock nuts on the height control sensor link. Turn the bolt of the height control sensor link to adjust the length. HINT: If raising the vehicle height, lengthen the link. If lowering the vehicle height, shorten the link. Turning the bolt of the height control sensor link 1 revolution changes the vehicle height by about 7.3 mm (0.287 in.). Check if the height control sensor link dimension shown in the illustration is less than the maximum value. Maximum dimension: 18 mm (0.71 in.) Tighten the lock nuts. Torque: 5.4 N*m (55 kgf*cm, 48 in.*lbf) NOTE: Make sure the ball joint and bracket are parallel when tightening the lock nuts.
- ADJUST HEIGHT CONTROL SENSOR LINK SUB-ASSEMBLY (for Rear) Adjust the rear vehicle height by moving the installation position of the link on the lower arm. HINT: When the link is moved 1.0 mm (0.039 in.), the vehicle height is adjusted by about 1.5 mm (0.059 in.). Torque: 5.4 N*m (55 kgf*cm, 48 in.*lbf) Perform vehicle height offset calibration once again. Inspect the vehicle height once again.
- INSPECT WHEEL ALIGNMENT Front: Inspect the wheel alignment (see «ADJUSTMENT» ). Rear: Inspect the wheel alignment (see «REAR WHEEL ALIGNMENT» ).
SYSTEM DESCRIPTION
- AIR SUSPENSION SYSTEM DESCRIPTION The suspension control ECU operates the compressor & motor with the dryer and uses the solenoid valves to control the vehicle height by analyzing the information based on the switches, sensors and input signals. Through the 4 height control sensors, the suspension control ECU detects changes in the vehicle height that result from the number of occupants or the amount of the load. Then, the suspension control ECU controls the height control solenoid valves and the compressor & motor with the dryer in order to automatically adjust the vehicle height to a constant (normal) level. Furthermore, 2 vehicle heights can be selected by operating the height control switch: HI and Normal. In cases such as when the vehicle is jacked up, the auto leveling function is prohibited by turning the engine switch off. In cases when the vehicle is to be jacked up with the engine running, the height control function can be stopped by connecting terminal 11 (OPA) and 4 (CG) of the DLC3 connector. The absorber control switch selects the shock absorber damping force (COMFORT, NORMAL or SPORT). Function of components COMPONENTS FUNCTION CHART Component Function Suspension Control Actuators Changes the damping force. Suspension Control Relay (AIRSUS) Supplies electricity to the compressor motor. Height Control Solenoid Valves Supplies and discharges compressed air to and from air chambers in 4 pneumatic cylinders (front left and right, rear left and right). Height Control Compressor Supplies compressed air to increase the vehicle height. Exhaust Solenoid Valve Discharges compressed air from the pneumatic cylinders to lower the vehicle. Height Control Sensors Detects the vehicle height and displacement volume of the suspension caused by unevenness of the road. Left Front Acceleration Sensor Detects the front left body vertical accelerated motion. Rear Acceleration Sensor Detects the rear body vertical accelerated motion. Height Control Indicator Light Displayed on the combination meter when the height control switch position is on HEIGHT HIGH. Height Control Switch Selects the vehicle height (NORMAL/HEIGHT HIGH). Absorber Control Indicator Light Comes on indicating that damping force is in "SPORT or COMFORT" mode by the damping mode select switch, and warns that a malfunction has occurred in the suspension control system. Absorber Control Switch Selects the damping force (COMFORT/NORMAL/SPORT). Skid Control ECU Receives the signals of the stop light switch and speed sensor, and sends them to the suspension control ECU. ECM Receives the signals of the throttle opening angle, shift lever position, and IC regulator, and sends them to the suspension control ECU. Suspension Control ECU Controls the damping force and vehicle height according to the operation modes. Blinks the damping mode indicator light to warn the driver when the ECU detects a malfunction in the suspension control system. When changed to the diagnostic mode, indicates any malfunction by DTCs (Diagnostic Trouble Codes). Detects the front right body vertical accelerated motion.
DESCRIPTION
The height control sensor changes its resistance value based on changes in vehicle height. The suspension control ECU outputs a fixed voltage of 5 V to the height control sensor's SHB terminal. If the sensor's resistance value changes, the sensor's voltage value changes accordingly. The suspension control ECU then inputs the voltage value from the sensor to detect the vehicle height change.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1711 | With the engine switch on (IG), a voltage of 4.7 V or more, or 0.3 V or less at right front height control sensor is detected for 1 second. | Wire harness or connector Front height control sensor RH Suspension control ECU |
| C1712 | With the engine switch on (IG), a voltage of 4.7 V or more, or 0.3 V or less at left front height control sensor is detected for 1 second. | Wire harness or connector Front height control sensor LH Suspension control ECU |
| C1713 | With the engine switch on (IG), a voltage of 4.7 V or more, or 0.3 V or less at right rear height control sensor is detected for 1 second. | Wire harness or connector Rear height control sensor RH Suspension control ECU |
| C1714 | With the engine switch on (IG), a voltage of 4.7 V or more, or 0.3 V or less at left rear height control sensor is detected for 1 second. | Wire harness or connector Rear height control sensor LH Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 16
The acceleration sensor (up & down G sensor) detects the upward and downward acceleration of the vehicle, and outputs it as a voltage to the suspension control ECU. Up & down G sensors are installed in 3 locations: 1) the suspension control ECU, 2) the driver side instrument panel, and 3) the rear quarter. Each up & down G sensor independently detects the upward and downward acceleration. During a test mode inspection, the suspension control ECU reads the fluctuations in each sensor's signal. If a sensor's signal does not fluctuate, test mode DTCs C1796, C1797 and C1798 are output.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1715 C1796 | With engine switch on (IG) and signal of 9.8 m/s 2 or more input into front acceleration sensor RH, either of following is detected for 1 second or more: power voltage of front acceleration sensor RH is 5.5 V or more, or 4.3 V or less | Suspension control ECU (Houses front acceleration sensor RH) |
| C1716 C1797 | With engine switch on (IG) and signal of 9.8 m/s 2 or more input into front acceleration sensor LH, either of following is detected for 1 second or more: power voltage of front acceleration sensor LH is 5.5 V or more, or 4.3 V or less | Front acceleration sensor LH Wire harness or connector Suspension control ECU |
| C1717 C1798 | With engine switch on (IG) and signal of 9.8 m/s 2 or more input into rear acceleration sensor, either of following is detected for 1 second or more: power voltage of rear acceleration sensor is 5.5 V or more, or 4.3 V or less | Rear acceleration sensor Wire harness or connector Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 17
The absorber control actuator switches the damping force depending on the suspension control ECU signals.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1731 | When either of the following is detected: An actuator open-circuit signal is detected for at least 1 second when the actuator operates. An actuator short-circuit signal is consecutively detected 8 times when the actuator operates. | Front absorber control actuator RH Wire harness or connector Suspension control ECU |
| C1732 | When either of the following is detected: An actuator open-circuit signal is detected for at least 1 second when the actuator operates. An actuator short-circuit signal is consecutively detected 8 times when the actuator operates. | Front absorber control actuator LH Wire harness or connector Suspension control ECU |
| C1733 | When either of the following is detected: An actuator open-circuit signal is detected for at least 1 second when the actuator operates. An actuator short-circuit signal is consecutively detected 8 times when the actuator operates. | Rear absorber control actuator RH Wire harness or connector Suspension control ECU |
| C1734 | When either of the following is detected: An actuator open-circuit signal is detected for at least 1 second when the actuator operates. An actuator short-circuit signal is consecutively detected 8 times when the actuator operates. | Rear absorber control actuator LH Wire harness or connector Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 18
The front height control valve independently opens and closes paths to the pneumatic cylinder for the front wheel side by receiving signals from the suspension control ECU.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1741 | When either of the following is detected: With the height control valve not activated, an open signal of the height control valve is detected for 1 second or more. With the height control valve activated, a short signal of the height control valve is detected 8 times successively. | Front height control valve Wire harness or connector Suspension control ECU |
| C1742 | When either of the following is detected: With the height control valve not activated, an open signal of the height control valve is detected for 1 second or more. With the height control valve activated, a short signal of the height control valve is detected 8 times successively. | Front height control valve Wire harness or connector Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 19
The rear height control valve independently opens and closes paths to the pneumatic cylinder for the rear wheel side by receiving signals from the suspension control ECU.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1743 | When either of the following is detected: With the height control valve not activated, an open signal of the height control valve is detected for 1 second or more. With the height control valve activated, a short signal of the height control valve is detected 8 times successively. | Rear height control valve Wire harness or connector Suspension control ECU |
| C1744 | When either of the following is detected: With the height control valve not activated, an open signal of the height control valve is detected for 1 second or more. With the height control valve activated, a short signal of the height control valve is detected 8 times successively. | Rear height control valve Wire harness or connector Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 20
The exhaust valve is installed onto the height control compressor. Based on signals from the suspension control ECU, the exhaust valve opens the exhaust solenoid valve, which releases the high pressure air within the system out of the vehicle. The exhaust valve operates until the target vehicle height is achieved. When achieved, the height control sensor outputs a signal to the suspension control ECU to stop the operation of the exhaust valve.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1745 | When either of the following is detected: With the exhaust valve not activated, an open signal of the exhaust valve is detected for 1 second or more. With the exhaust valve activated, a short signal of the exhaust valve is detected 8 times successively. | Height control compressor (Exhaust valve) Wire harness or connector Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 21
The signal from suspension control ECU switches the suspension control relay on, and then the height control compressor motor starts.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1751 | When either of the following is detected: With the suspension control relay not activated, an open signal of the suspension control relay is detected for 1 second or more. With the suspension control relay activated, a short signal of the suspension control relay is detected 8 times successively. | Suspension control relay Wire harness or connector Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 22
The signal from the suspension control ECU turns on the suspension control relay. At that time, battery voltage is input to the height control compressor motor through the suspension control relay. The height control compressor motor starts.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1752 | With the suspension control relay activated, a lock signal of the height control compressor motor is detected for 4 sec. or more. | Suspension control relay Height control compressor (compressor motor) Wire harness or connector Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 23
The signal from the suspension control ECU operates the suspension control relay and the height control compressor motor starts. The height control compressor motor operates until the targeted vehicle height is reached. Then the height control sensor sends the signal to the suspension control ECU, and stops the height control compressor motor.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1761 | While suspension control relay is ON, vehicle height does not reach target for 3 minutes or more | Air leakage from the air tube or each valve Suspension control relay Height control compressor Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1762 | With the exhaust valve activated, the vehicle does not go down to the standard vehicle height after 6 minutes have elapsed. | Air tube Front height control valve Rear height control valve Height control compressor |
DETECTION CONDITION REFERENCE CHART
If a malfunction in the suspension control ECU is detected, DTC C1781/81 is output.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1781 | Suspension control ECU malfunction is detected | Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| 1782 | While engine switch is on (IG), detection that voltage at terminal B is 10 V or less, or 16 V or more for 0.5 seconds | Battery Charging system Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 24
The speed sensors monitors the speed of the wheels, and sends an appropriate speed signals to the suspension control ECU through the skid control ECU. If trouble occurs in either the front speed sensor or rear speed sensor, DTC (C1783) is output.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1783 | Speed sensor circuit malfunction for 1 second or more. | Speed sensor Skid control ECU Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
The steering angle sensor signal is sent to the suspension control ECU through the CAN communication system. When there is a communication malfunction, it will be detected by the diagnosis function.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1784 | Steering angle sensor signal malfunction is detected, or steering angle sensor power malfunction signal is detected for 5 seconds or more | Steering angle sensor Steering angle sensor power source circuit Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
Scheme 25
The suspension control ECU receives signals from the steering control ECU via CAN communication.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1785 | While engine switch is on (IG), steering control ECU malfunction signal is received for 5 seconds | Steering control ECU |
DETECTION CONDITION REFERENCE CHART
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| C1787 | While engine switch is on (IG), acceleration sensor malfunction signal is detected for 1 second or more | Yaw rate & acceleration sensor |
| C1788 | While engine switch is on (IG), yaw rate sensor malfunction signal is detected for 1 second or more | Yaw rate & acceleration sensor |
DETECTION CONDITION REFERENCE CHART
- This DTC is stored when the suspension control ECU is initialized, and is cleared when the vehicle identification information received through CAN communication is correctly stored in the EEPROM.
- DTC C1789 is stored as the vehicle specification and data do not match when an incorrect ECM or AFS ECU are installed. DTC DETECTION CONDITION CHART DTC Code DTC Detection Condition Trouble Area C1789 When either condition is met: Vehicle identification information is not stored. The information stored in the suspension control ECU and the vehicle identification information received through CAN communication do not match. Suspension control ECU ECM AFS ECU
The suspension control ECU inputs signals from the skid control ECU, steering control ECU, steering angle sensor, yaw rate & acceleration sensor, ECM and TCM via CAN communication. When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system first.
| DTC Code | Detection Condition | Trouble Area |
|---|---|---|
| U0100 | While driving at 19 mph (30 km/h), ECM informs of CAN communication stop for 3 seconds or more | CAN communication line ECM Suspension control ECU |
| U0101 | While driving at 19 mph (30 km/h), TCM informs of CAN communication stop for 3 seconds or more | CAN communication line TCM Suspension control ECU |
| U0122 | Skid control ECU informs of CAN communication stop for 3 seconds or more | CAN communication line Skid control ECU Suspension control ECU |
| U0124 | Yaw rate & acceleration sensor informs of CAN communication stop for 3 seconds or more | CAN communication line Yaw rate & acceleration sensor Suspension control ECU |
| U0126 | Steering angle sensor informs of CAN communication stop for 3 seconds or more | CAN communication line Steering angle sensor Suspension control ECU |
| U0130 | 5 seconds after engine switch is turned on (IG), CAN communication from steering control ECU stops for 3 seconds or more | CAN communication line Steering control ECU Suspension control ECU |
| U0132 | CAN bus turns OFF 10 times in a row | Suspension control ECU |
DETECTION CONDITION REFERENCE CHART
The absorber control switch and height control switch send signals to the mirror switch through LIN communication, and the suspension control ECU sends signals to the mirror switch through CAN communication. If an absorber control switch or height control switch signal is input into the suspension control ECU, the ECU sends a signal to the combination meter, which then illuminates the indicator light.
Scheme 26
When the engine switch is on (IG), the driver side junction block AIRSUS relay turns ON, and power is supplied to the suspension control ECU.
Connect terminals 12 (TS) and 4 (CG) of the DLC3 with the engine switch off. When the engine switch is turned to the on (IG) position, test mode will start and then the DTCs will be output.
Scheme 27
See also:
• DIAGNOSIS SYSTEM
• DTC CHECK/CLEAR
• REMOVAL
• REMOVAL
• DIAGNOSIS SYSTEM
• REMOVAL