A few months ago my front right Airshock blew out. I Replaced it with the Arnott shock. several days later the CATS System Fault messege appeared. The car is now riding like a Covered Wagon. Every pebble i drive over feels like a boulder. Ride height is normal and even all the way around. Just stiff as a board. Compressor runs normally with no hissing sounds anywhere. I have Pulled and Checked every fuse in the car in all 3 panels. All fuses are good. I disconnected and reconnected all Shock Sensors. I pulled the spare tire and unplugged and reconnected the AIR modules near the tank. I disconnected the batter for 30 minutes and touched the Neg and Positive cables in hopes of clearing any erroneous codes. No Luck.,,, Im so fed up with this over Tech'd car and im not spending another dime on fixing things. is there any way i can just disable or bypass the CATS system and have a smooth ride?

 

Hi Catsgame,

I assume that since you replaced only one front air spring/damper assembly, it was an original Bilstein unit that had been rebuilt by Arnott. My understanding is that Arnott's proprietary units do not support CATS, so if you had installed one of their units, your CATS fault would have appeard immediately. Do I understand correctly?

My first suggestion would be to call Arnotts and explain your problem and ask for their help in resolving the problem.

If Arnott claims their unit should support CATS, my second suggestion would be to have the Diagnostic Trouble Codes (DTCs) scanned to help pinpoint what has triggered the CATS fault. A malfunctioning CATS solenoid or any number of other electrical faults can trigger the CATS fault.

Just a quick outline of the CATS system operation (called ECATS now in the X350 for "Enhanced"): The default mode of the air springs is Firm. To switch the ride to Soft, the CATS module, which is built into the Air Suspension Control Module (ASM), sends a 400Hz pulse width modulation (PWM) signal to the CATS solenoids. The solenoids are mounted in the tops of the air spring/shock units where the electrical connectors attach. The solenoid responds by modulating the valving in the shock to soften the ride. The CATS module determines when to activate Soft mode based on signals from a front accelerometer (behind the right front wheel arch liner toward the rear) and a rear accelerometer mounted on the left rear inner wheel well in the trunk, to the right of the telematic stack (where the CD changer is if you have one). Other inputs taken into account include the brake switch, brake pressure, ABS system, engine torque rate, and vehicle speed.

I'm hoping your issue will prove to be either a problem with the CATS solenoid in the Arnott unit you received, and will therefore be corrected by Arnott, or something else like an electrical fault that is identified by a DTC and is easy to track down and resolve.

Please keep us informed.

Cheers,

Don

 

Well i cant say enough good things about Arnott..... This all had begun WHen i received the replacement shock for the front i forgot to remove the nuts from the strut bolts before putting in place (stupid i know), ofcouse i didnt relize it untill it was too late and Wedged in place. I had to bang on it with a hammer for several hours to get it back out so i could correctly install it. Im sure all that banging wasnt good for it.... This is what i figured was causing my problem now, with the CATS sensor. I told Marvin at Arnott what i had done and they Sent me a brand new replacement sesnor for FREE. it only took 5 minutes to swap the sensors and it rides like a $70k car again

 

Thats some good news right there. Well Done Arnott.