[gravure]

Hi,
I own a 2004 RR, VIN 4A141872 with 198,000 miles with a problem. I hope someone can advise.


New battery installed and have 14.4 volts at 2000rpm.


After 20 minutes of driving straight roads then slowing down and rounding a 90 deg corner, the DSC, ABS,Trans Failsafe mode & Air suspension Failure errors appear. After stopping and then restarting engine, I can still drive normal speeds (Trans Failsafe disappears) and the only issue aside from the dash lights is the suspension rides low. If just left overnight, all appears well the following morning. Error messages gone and the suspension pumps up. Also on other occasions, after disconnecting neg earth strap, all errors messages disappear and can drive normally until the next slow 90 deg corner.
With an Allcomms module several errors are detected (Can Bus missing node - ABS ECU, Steering angle sensor -Incorrect CAN message, Anti-lock Brake Faults: ABS ECU, ABS supply) and all errors clear except Air Suspension - CAN bus Fault. I rebuilt the suspension pump and perhaps I need to replace the front suspension airbags since they do sink .5 inch overnight. Just need advice as to course of action. Thanks, Bill

 

[RRToadHall]

At that mileage is not at all surprising you have leaks in your front struts. They are most likely the second pair. Bus faults can be low voltage issues. You may have a top notch alternator and new battery but if anyone of your high tension cables are dirty at either end or suffering from corrosion the resistance will keep that 14.4 from getting where it need to go.

 

[brad s1]

Make sure the suspension isn't leaking... that said I had this exact problem for YEARS on an 04, I tried everything to fix it. Eventually I did tie rod ends and brought the car to the dealer for alignment, the issue never came back. I later discovered the dealer calibrates various things (suspension/steering angle/etc) that remedied the problem. When the car goes far enough out of alignment 10-20 min into a drive the thing lights up like an xmas tree and there is no other fix but a proper alignment. Bringing it to chain shop will not work, either a dealer or independent.