I replaced the rear air shocks, relay, and air compressor on my 04 XJ8. Car is now all the way to the ground and it seems as the aircompressor is not coming on. I have checked all lines with soapy water for leaks and all fuses and relays. Please advice

Thanks

 

Why did you replace all these? We need more info. I would first bypass the relay and see if the compressor will run. Can't check for leaks if the shocks are flat.

 

I replaced all three because that is what the dealer told me that needed replacing. I spliced the front air lines and manually put air in the front shocks with a small air compressor and they seemed to be holding the air over night. The rear shocks are brand new. It seems that there is something that is not allowing the signal go to the air compressor to turn on

 

Did the compressor run before. How do you "splice" the tubing? What were the symptoms before you listened to the dealer?

 

the initial problem was a front air shock that was leaking. While it was in my garage for a couple of days waiting for the new shock to arrive, the car went completely down. I finally changed the bad air shock when it arrive in the mail. This was not the first time I had replaced a shock. The two times I did it before, I just drove it for a little bit and the car would raise. But this time it didn't raise at all after I replaced it. I figured it might be the compressor, but when I took the compressor off, I gave it 12 V and it came on. I put it back in the car. The car was way too low to get on trailer, so I split the airline going to the front right shock with a quick snap connection and a Schrader valve to manually get enough air in the front shocks to get it on my trailer and take it to dealer. I had them diagnose only, and they concluded that it was both rear shocks, compressor, and relay. So I changed everything they told me was wrong, however, the car is still not raising. Could it be the module, valve block, or pressure sensor?

Thanks Red

 

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Try driving it around the block. Could take up to 20 mins to rise.

 

Wouldn't recommend that. Try jumping the relay and see if the compressor will run. It could be virtually anything at this point.

This kind of aggravation is the main reason I now have coilovers.

 

I have tried driving it around the block to no avail, I'm concern with continuing that it will damage the new rear shocks I just installed. I do concur with Red about the coilovers. I just feel stuck with a new compressor and new rear air shocks

 

Have you gotten any fault messages. Any codes?

 

fault messages, "vehicle to low", DTC 2302

 

Check you haven't caught the compressor exhaust tube when you fitted the compressor to the bumper iron it can get squashed and not inflate shocks

 

ok, thanks Gavin. I did however, manage to bypass the relay and get the compressor running, I let it run for about two minutes. I have not figured out how to bypass the solenoid. I will recheck the exhaust tube in the morning and let you know the results.

 

You might need to have the suspension height recalibrated. The system has an ASM to control each air spring via the valve block and air tank. Height inputs come from sensors at front and rear. According to my X350 technical notes, recalibration is required after: -

1. ASM is replaced
2. A height sensor is removed and reinstalled
3 A height sensor is replaced.

Your fault display should have thrown up one or more fault codes, so get these read off then you can start to see what might be wrong.

 

thanks Fraser, though I did not perform any of the three listed, I did do some work on it, I will get it up on my trailer and take to dealer for recalibration. Thanks again

 

http://www.captainjaguarscathouse.co...ec%20Guide.pdf

Electrical Guide

 

Multiple keys cycles and yes drive it around the block slowly several times. It will almost always come up. Notice i said slowly as avoid speed bumps, potholes etc. If its smooth you can and should go above 11mph

 

It's been awhile since I've changed an airshock, but my recollection was that the height sensor has to fooled into thinking it was in the same position before the change as after. To do this, I recall lifting the car, removing the wheel and then disconnecting the battery before touching the height sensor. After changing the shock, I then reconnected the battery with the shock extended just the same as it was before the change. This ensures the module thinks the shock was undisturbed and will not require recalibration.

 

I wanted to post an old procedure for spring replacement that outlines the issues pretty well:

I've been hesitating answering this because it can become complex and unorthadox without a WDS, or whatever they're calling it these days.

You can pull off the air spring change without reprogrmming the ASM. You have to deviate from the JTIS though. First, you have to understand the basic operating modes and strategies of the AS system. To begin, the ASM will need to be calibrated (suspension height set) only if:

Any height sensor is removed, then reinstalled
The ASM is replaced
or a height sensor is replaced.
While the ASM is active and powered up.

So, you don't want to do any of these, even though JTIS says to remove the height sensor. The ASM is using non-volatile memory to "remember" the inputs of all sensors when it is in certain modes, or when the battery is disconnected. So, you need to outsmart it and create that situation while you are R/Ring the air spring and when the ASM wakes back up.

Briefly, there are five modes the ASM takes depending on "activity". The modes are:

Sleep mode
Preliminary mode
Post mode
Stance mode
Drive mode

You'll be focused on one of these - sleep mode. The ASM goes into sleep mode 30 minutes after the ignition is switched off and the last door or trunk activity is detected. The entire air suspension system shuts down during this time (enters sleep mode) and, if the car is not used, wakes up on a 24 hour clock to check height. At 24 hour intervals, the ASM makes adjustments in height by measuring the lowest sensor and adjusting dwonward so the suspension is even.

Basically, you want to catch the system before sleep mode. You're going to do that by positioning the vehicle where you will work on it, get it raised off the ground and suspended, then disconnect the battery before sleep mode (sooner than 30 minutes after shutting the engine down). By doing this, the ASM will store its inputs from the height sensors with the suspension fully extended. In essence, you're going to perform the surgery on the air springs while the ASM is anesthetized thinking the suspension is in the full extended position. That is what it is going to remember when it wakes up. If it doesn't see that, you'll need to recalibrate the ASM.

Follow most of the JTIS steps now - depressurize the springs, you can use a floor jack to take weight off the airspring, etc., not removing the height sensors. Replace the air springs, make all connections, make sure the suspension is sitting precisely the way it was before disconnecting the battery. Put the wheels back on so you are ready to sit the car back down on its suspension. Connect the battery, lower the car back on its tires. Start the engine so the ASM moves from preliminary mode to stance mode. This will activate the compressor which the ASM will be demanding to reestablish the original ride height. You should get a "ride too low" restriction message as the compressor needs to fill the reservoir plus the entire suspension. Even If the compressor is strong, this can take a while because the ASM times out the compressor to preserve it, keep it from overheating. It will cool back down to a preset temperature before coming back on. Giv it the time while the engine is idling, and...with luck...the fault ride too low will extinguish and you'll be on your way...hopefully not to the dealer.

 

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