When vehicles are equipped with air suspension, an ECAS electronic control system (Wabco) is installed
The system contains a microprocessor unit 18 (figure) located under the instrument panel, a suspension remote control 19 installed on the left side of the drivers seat, an electropneumatic valve unit 17 and an inductive suspension position sensor 16 installed in the rear of the right side member of the frame.
Control lamps 8 and 9 (Figure 2) with suspension control symbols are installed on the main instrument panel, switch 10 of the second transport position is on the additional instrument panel on the right side of the driver.
The system also has diagnostic lines connected to diagnostic socket 11.
The fuses FU6, FU7 of the suspension control system are installed in the fuse box (Figure 3), which is located on the ABS electronics circuit board.
The location of the buttons on the remote control is shown in fig. 2
Scheme of electrical connections of the elements of the system is shown in fig. 3.
1. When the starter switch is turned on in the “instruments” position, it conducts a preliminary diagnosis of all its devices and control lamps. In this case, both control lamps 8 and 9 (Fig. 4) light up and go out after 2-3 seconds if the control unit has not detected any errors.
Then, if there is sufficient pressure in the reservoir and the handbrake is released, the system automatically sets the suspension to the position it was in at the time of the previous power off.
2. Allows you to adjust the height of the saddle (platform), as well as memorize any two height positions and, if necessary, set any of them using the remote control.
Note. Control from the remote control is carried out with the vehicle stationary or at speeds below 30 km/h.
3. Automatically maintains the previously set height and locks the suspension when braking.
At a speed of more than 30 km/h, it automatically sets the "transport" height position, at a speed of more than 60 km/h - the second "transport" position (to reduce the height of the center of gravity and increase vehicle stability).
The system also allows you to set the first or second "transport" height position using switch 10 (Fig. 4).
4. Provides built-in self-diagnosis while driving and, if a malfunction or error is detected, signals the driver by turning on the red warning lamp.
The remote control is turned on and off with the button 7 (Fig. 4), while, accordingly, the lamp 8 on the remote control should light up or go out.
Remote control is as follows:
- —raise/lower when buttons 1, 2 are pressed (Fig. 2);
- - setting the height to the "transport" position by pressing button 4;
- - the set level is written to the memory by pressing the button 3 ("STOP") and not releasing it - to the button 5 or 6 ("memory" M1 or M2);
- - setting the height level previously recorded in the memory by pressing the button 5 or 6 ("memory" M1 or M2);
- - interrupting the process of changing the height level
- —when button 3 ("STOP") is pressed.
The red control lamp 8 (Fig. 5) signals the health / malfunction of the system, and also serves as a means of displaying information about the type of malfunction during diagnostics.
The yellow indicator lamp 9 indicates the state of the "transport" position of the suspension and may go out if not If the altitude level is set to the specified position, or stay on if the altitude level is different from the specified one.
When setting the height to the “transport” position, sensor 16 (Fig. 1) must be in the position shown in Fig. 6.
Setting the lever 2 to a horizontal position with the set "transport" position (370 mm) is carried out by adjusting the length of the rod 3.
The system does not require any special maintenance other than a performance check
Control check of the system
1. Before checking the function, make sure that there are no compressed air leaks from the pneumatic system.
Enable mass button.
Turn the lock on the starter and instruments to the "instruments" position. At the same time, they should light up at the same time and after 2 seconds. turn off all control lamps of the air suspension system (Fig. 5).
- 2. Start the engine and bring the pressure in the air suspension receivers to normal (6.9-8.2 kgf/cm2).
- 3. If the yellow transport position control lamp is lit on the instrument panel, this indicates that the vehicle suspension is in a position other than the transport position, and it is necessary to set it to the transport position by pressing button 4 on the remote control (Fig. 3).</li >
When the transport position is established, the indicator lamp should go out. Make sure that the air suspension system has set the nominal height (transport position) of the loading platform (see Fig. 5).
- 4. Change the level of the platform using the "up" and "down" buttons, while the yellow "transport" indicator lamp should light up.
- 5. Write any two platform height settings to the memory of the electronic unit.
To do this, you need to set it to the desired position using the "up" or "down" buttons on the control panel, press the "STOP" button and any of the "M 1" (memory 1) or "M2" (memory 2) buttons, without releasing the STOP button (Fig. 3).
- 6. Move the suspension to the “transport” position by pressing the corresponding button, and check whether the system sets the platform height previously recorded in the “memory” by pressing the buttons “M1” and “M2” of the remote control.
In this case, when the height of the platform approaches the level set or previously recorded in the “memory”, the characteristic noise of switching valves will be heard (you can stop the regulation by pressing the “STOP” button).
After that, check whether the “transport” position of the suspension is automatically set at the start of the movement (at a speed above 30 km / h, the “transport” position is automatically set and the yellow control lamp on the instrument panel should go out).
Possible malfunctions in the suspension control system and how to fix them
Turning the starter lock key to the Gauges position does not light up the control lamp
- There is no or low voltage of the vehicles on-board network, the battery is discharged
Check the voltage of the on-board network, fuses, charge the battery
- There is no supply voltage to the control unit (CU)
- Check CU power fuses and wiring.
- Troubleshoot wiring and replace fuses
When turning the key of the starter lock to the "Instruments" position, one of the control lamps does not light up
- malfunction of the control lamp or wiring
Replace pilot lamp, troubleshoot wiring
- Faulty control unit
Replace control unit
After turning the key to the "Instruments" position, the red control lamp does not go out
- Malfunction of the sensor coil, poor contact in the connector for connecting the sensor to the cable, cable break
- Check the resistance of sensors and cables, determine where the fault is.
- Troubleshoot by replacing sensor or cable.
- Faulty coils of solenoid valves, broken contact in the connector, faulty connecting cable
Check the resistance of the solenoid valve coils, cable and connector.
- Contact failure in the switching block of the block or circuit of terminal B7 of the tachograph
- Find out where the problem is.
- Troubleshoot by replacing modulator or cable
- Restore contact in the block or circuit of the tachograph
- Faulty control unit
Replace control unit
After turning the key to the "Instruments" position or when driving, the yellow control lamp lights up and does not go out
- Lack or insufficient pressure of compressed air in the receiver
Start the engine and bring the pressure in the receivers to normal (6.9—8.2kg/cm2)
- The fastening or installation of the sensor, or the sensor lever is broken
Check the mounting of the sensor and the installation of the sensor arm.
- The sealing of the air spring or pipelines is broken
- Check the system for leaks.
Red indicator light comes on or flashes while driving
- Broken contacts, short circuit or breakage of sensor cables or electromagnetic cables
- Check wiring, electrical connections and resistance of sensor and solenoid valves.
- Replace failed products
There are no suspension reactions when pressing the remote buttons
- System power not connected, fuse broken
Check power circuit, replace fuse
- The remote control is not connected or turned on
Connect or turn on the remote