The diagnostic socket enables the exchange of information between the various control units connected by the bus system and Land Rover approved diagnostic equipment. This allows diagnostic information to be quickly retrieved and specific functions to be programmed using Land Rover approved diagnostic equipment.
Troubleshooting
The air suspension control unit performs fault diagnostics and plausibility checks. Only faults that the control unit can detect by direct measurements are detected:
- Sensor wiring faults
- Valve wiring faults
- Sensor and actuator power supply circuit faults
- Tire faults
- Control unit hardware malfunctions
Validity checks and behavior checks of signals:
- Incorrect change in average altitude value Too slow change in altitude
- Too slow altitude change
- Gallery Pressure Does not increase quickly enough when requesting to fill receiver Increases when system is inactive Too low when requesting to increase altitude Increases too quickly when filling receiver Does not decrease when purging gallery Pressure changes too much when system is inactive.
- Doesn't increase fast enough when asked to fill the receiver
- Increases when the system is inactive
- Too low when requesting increased altitude
- Increases too quickly when filling the receiver
- Does not decrease when blowing through the gallery
- Pressure changes too much when the system is inactive
- Compressor temperature Sensor voltage too low - head and brush sensors (short circuit to battery) It takes too long to read data after the compressor has been running long enough - head and brush sensors Does not increase when the compressor is on - head sensor only
- Sensor voltage too low - head and brush sensors (short circuit to battery)
- It takes too long to read data after the compressor has been running long enough - head and brush sensors
- Does not increase when the compressor is on - only the head sensor
- Operation of sensors "Floating" signal Constant rotation during movement
- "Swimming" of the signal
- Constant rotation while moving
When a fault is detected, the air suspension control unit attempts to maintain ride comfort and as much functionality as possible.
The functionality of the system is determined by the severity of the malfunction.
Malfunctions
Faults are categorized according to their severity and affect the system operation as follows: (here 1 is a minor fault and 5 is a major fault):
- Malfunctions (hardware) height sensors and malfunction of the receiver valve block Full functionality is maintained without "subtle" features, for example, if the bypass valves are disabled, unevenness of the road surface is not compensated.
- Full functionality is maintained without "subtle" features, for example, if the bypass valves are disabled, unevenness of the road surface is not compensated.
- Pressure sensor faults, compressor faults, shock absorber valves stuck in closed position No vehicle speed signal The vehicle returns to road mode on next request. Leveling at "current" altitude.
- Vehicle speed signal missing
- At the next request, the vehicle returns to on-road driving mode.
- Alignment at the "current" altitude.
- Jamming of the receiver valve in the open state, jamming of the exhaust valve in the closed state at a height below the height of the road mode, jamming of the shock absorber valves in the open state at a height above the height of the road mode. At the next request, the vehicle returns to road mode. Alignment is not performed at the "current" height.
- At the next request, the vehicle returns to on-road driving mode.
- Alignment at the "current" height is not performed.
- Multiple height sensors faulty, lateral rotation while driving, calibration failure. Vehicle drops onto compression buffers.
- The car is lowered onto the compression buffers.
- ABS module malfunction, CAN bus malfunction If the air suspension control unit loses communication with the ABS module, or the ABS module reports a malfunction, the air suspension control unit immediately returns the "default" height below the on-road driving height. When the default height is reached, the control unit continues to level the vehicle at this height. It is unlikely that the air suspension control unit is malfunctioning. Once the malfunction is corrected, the air suspension control unit will resume full operation, but an error will be stored in the control unit's memory.
- If the air suspension control unit loses communication with the ABS module, or the ABS module reports a malfunction, the air suspension control unit immediately returns the "default" height to below the on-road driving height. Once the default height is reached, the control unit continues to level the vehicle at that height. It is unlikely that the air suspension control unit is faulty. Once the malfunction is corrected, the air suspension control unit will resume full operation, but an error will be stored in the control unit's memory.
In case of major faults, the control unit does not level the vehicle at the "current" height. The control unit stops changing the height until a manual or automatic height change request is received. The control unit returns to the standard height, if possible, and stops controlling when this height is reached.
If the suspension is in a position above the on-road height, the air suspension control unit will not be able to lower the suspension and all height changes will be stopped. The control unit will send a message via the high-speed CAN bus to the instrument cluster, which will display the maximum recommended speed on the message center display. Immediately stop changing the vehicle height in the following cases:
- Multiple height sensors faulty - vehicle on compression buffers
- Signs of unreliable turning were registered - the car is on the compression buffers
- Valve or solenoid failure - shock absorber valve stuck open with suspension height below road ride height or exhaust valve stuck closed with suspension height above road ride height.
- Jamming of the shock absorber valve or all valves (during diagnostics, the reliability of sensor signals is assessed).
If the height change is not possible, for example due to a stuck exhaust valve at the road height, or a compressor failure at the landing height, the control unit will not perform the leveling and height change.
In the event of a hardware failure of the air suspension control unit, the control unit disables all air suspension functions. The following hardware errors are recorded: memory errors, control unit failures and calibration errors.
Error messages
The air suspension system informs the driver of malfunctions via the air suspension switch LED and the instrument cluster message center.
For minor faults where the air suspension control unit can level the vehicle at the "current" height, the air suspension switch LED shows the current height.
In case of serious malfunction of the air suspension control unit, when the air suspension control does not work, all the LEDs of the control switch go out.
[The article is based on data from the website www.LRman.ru]
If, in the event of a malfunction, the air suspension control unit can detect the suspension height and it is not higher than the ON-ROAD mode height, the following warning will appear on the information center display: "air suspension fault max speed 30 mph (50 km/h)" (air suspension malfunction, max speed 50 km/h).
If the control unit cannot detect the suspension height, or the height exceeds the on-road driving height, cannot be lowered, and the vehicle speed is too high, an air suspension malfunction message is displayed.
If the only available height is on-road mode, a message is displayed indicating that there is a fault with the air suspension and that only normal height is available.
Comments on this article