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I remember that I measured the shock plug some years ago with two paper clips.
I think the value was zero Ohm, so I assume that inside the bilstein damper there is just the coil of a magnetic solenoid valve connected, but I'm not sure.
I am not an electronic but certainly there is a way to measure the impedance of the coil, but my simple multimeter cannot do that.
If you determine the impedance you should be able to connect a similar coil to fool the ASM to think the damper is still connected, right ?
I remember that I measured the shock plug some years ago with two paper clips.
I think the value was zero Ohm, so I assume that inside the magnetorheological damper there is just the coil connected.
I am not an electronic but certainly there is a way to measure the impedance of the coil, but my simple multimeter cannot do that.
If you determine the impedance you should be able to connect a similar coil to fool the ASM to think the damper is still connected, right ?
It is possible the coil has very low resistance, but a coil with any meaningful impedance will have some measurable DC resistance, even if it's just a fraction of 1 ohm. Impedance can be thought of as "AC resistance," but it's more complex than simple resistance because it also includes reactance (the combined effects of inductance and capacitance) and phase angle, and impedance varies with frequency. Measuring impedance is a lot more complex than measuring DC resistance, so I have to wonder if the ASM is measuring impedance to determine the presence of a fault, or if it is simply measuring for a range of DC resistance, or maybe just for conductivity (open the circuit and a fault is triggered).
As far as I have been able to determine, the Jaguar/Bilstein dampers are not magnetorheological. They do not use a fluid whose viscosity changes when subjected to a magnetic field. Instead, they use standard oil as fluid, and an electro-magnetically controlled solenoid valve at the top of the air spring/damper varies the flow of the fluid between two paths, altering the ratio for either Firm or Soft damping. The switching is controlled by a pulse-width modulated (PWM) signal from the ECATS system within the ASM to the coils in the damper solenoid valves.
I just checked the ECATS section of the Dealer Training Manual again, and it states the solenoids are controlled by a 400Hz PWM signal, and the solenoids are two-stage (open/closed) and specified at 5.4 ohm (whether that is DC resistance or impedance at 400Hz is not given). See pdf page 27 of the Air Suspension & ECATS section of the Dealer Training Manual, which you can download from the 'HOW TO' quick links thread on the home page of this X350 forum.
IIRC, someone posted a photo of the devices in the tops of Arnott's proprietary replacement air springs/dampers that fool the ASM to prevent the CATS warning. The device was about a little smaller than a golf ball and was wrapped in white braided fabric like that used to protect coils of wire, such as guitar pickups, inductors, solenoid coils, etc. At the time I assumed it actually contained a coil of wire to mimic the impedance of the original solenoid coils, but now I wonder if it just contained a resistor per 34by151's tests and was packaged and wrapped to fit nicely in the top of the Arnott air spring/damper unit.
I wonder if it just contained a resistor per 34by151's tests and was packaged and wrapped to fit nicely in the top of the Arnott air spring/damper unit.
It will need to absorb some current. Your normal 1/4 watt one will probably burn out. My Guess is it a 5w or 10w wire wound resistor.
Unplug the air suspension module located behind the rear seat back. It will take the it (the air suspension module) off line and the warning will go out. I've seen that resolve every issue, in my experience.
Unplug the air suspension module located behind the rear seat back. It will take the it (the air suspension module) off line and the warning will go out. I've seen that resolve every issue, in my experience.
Hi Cdubu,
Welcome to the Jaguar Forums. It's great to have you with us.
Apparently disconnecting the ASM only works on '04-'07 X350s that have not received a software update (mine has). It also does not work on later cars. On updated earlier cars as well as '08 and later cars the CAN network recognizes that the ASM is not communicating and triggers a fault. See this post from Doug at Arnott:
Don,
Thanks for the clarification. I wonder if you could push older software into the ASM (with an older DVD version of IDS before it went SDD) or get an ASM from an 07 and that would trick the system?
As no correction of the message #55 is possible anymore, this is the rectified tentatively quick start guide for Fernando and newer X350s, which is intellectual property of Cambo, Don B, 34by151 and others:
1. Disconnect the battery
2. Push in a fitting at the disconnected air tubes of the two front bags (or disconnect the tubes at the manifold in the boot and add a plug)
3. Reconnect the two front height sensors, strap the sensors in the correct (medium) position, put and/or fix the sensors somewhere. Later you can measure the resistances of the height sensors and replace each of it by two resistors.
4. Mount two wire wound resistors 5,4 ohm / 10 Watt instead of the front shock electric plugs
5. Be careful by doing all that
6. Reconnect the battery
7. Do a test drive
8. Report your experience here
Reading from the height sensor feedback vary from 2-3 Volts
As I stated earlier the readings will vary from car to car depending on the height set in SDD and the adjustment of the sensor
The sensor is not resistive but that does not matter. The important part is the voltages fed back to the ASM on pins
CR90-2, CR90-5, CR90-8 and CR90-11
Some will have 4 sensor systems other 3 sensor
In my case I have 4 fitted with 3 used (updated ASM firmware)
From page 7-33 of the dealer training guide
"The damper operation and design are carry over, each unit having a 400Hz PWM, two stage (open / closed) 5.4 ohm solenoid"
This is consistent with my measurement of 6-7 ohms
I have run a test today with 10 ohm and 150 ohm resistors fitted in place of the shock solenoids
Both resistors were 10W ones. You may get away with lower wattage but I had these in the parts bin
Neither presented any errors.
The Pins for this are in pairs
CR89-4 & CR89-1 LH Front
CR89-5 & CR89-10 RH Front
CR89-7 & CR89-2 LH Rear
CR89-8 & CR89-11 RH Rear
One thing I do on the track is remove the plugs to force the system in hard damping. Next step for me is to wire in a 4 pole rotary switch. Plan is to mount though to the boot near the ski hatch. The resistors will be behind the seat and the selector in the boot.
Quick and easy for the track switch in the resistors fooling the ASM, isolating the struts forcing them into hard mode. Track day over flick the switch
Getting back to the issue at hand (coils front and Air rear)
Id set the voltage feedback on pins CR90-2 and CR90-5 to approx 2.5volts
A pair of equal sized resistors in series will do this
Use a high value to minimise the current say 1meg ohm
So fit 1M Ohm resistors between these pins on the ASM
CR90-1 & 2
CR90-2 & 3
CR90-4 & 5
CR90-5 & 6
This will feedback 2.5 volts to the ASM on the feedback pins
CR90-2 & 5
Last step is to calibrate the suspension in SDD.
This will store these feedback values for the front suspension in the ASM.
Finally level the rear in SDD using Cambo's tutorial.
Question I do have. Where are the height sensors. Are they attached to the strut or somewhere on the car.
You have them unless they have been removed
The sensors are mounted on the front and rear subframe assemblies. They have arms that then connect yo the wishbone to measure the height
I need to get the appropriate resistor then connect it to in series to the shock connection.
Disconnect the battery and I should be set.
I haven't touched the height sensors so I should be OK as far as that goes. Or since with the S type will ride an inch lower I have to manipulate the reading to make it taller than it actually is?
07-30-2016, 09:11 AM
shock plug measure
tentatively quick start guide
