Rear Air Suspension Problems

[HUMTECH]

I would start by replacing the relay. It is located below the brake master cylinder on the 03 model year just above the frame rail(dont know the part #). Then try to clear all codes. On level ground with the engine running check your level sensor data again, they should read between 2.5 and 3.5 volts, any lower or higher and they are not in the proper range when sitting still and level. If the right one still is reading high you can try to adjust it but will likely need to be replaced. If you do replace it you will then require a trim height learn procedure.