I have a '99 SLS that has been a dream since I purchased it in 11/2006. For the last week to ten days, I have had an intermittent ABS and Traction Control warning light on and an intermittent Service Suspension message in the DIC. I have checked the codes and they are as follows:
P1602 Current Knock Sensor Module Performance
P1644 History Traction Control Delivered Torque Output Circuit
C1736 History Compressor Relay Short to GND/Open
C1780 History Loss of Steering Position Sensor
C1783 Current ICCS2 DL Left Output Short to GND
C1785 Current ICCS2 DL Right Output Short to GND
U1040 History Loss of Class 2 Communication with ABS
U1255 Current Class 2 Communication Malfunction
(Serial Data Line Malfunction)
These warning lights and messages are intermittent in that they seem to come and go with little or no rhyme or reason. When the warning light condition exists, I lose the variable speed steering. I still have power steering but it is very stiff during this condition. I have also noticed that when the condition exists, the AC/Heat system is acting strangely in that it will not operate as set. I leave the system on Auto at all times and when the warning light condition exists, it will either not work or will blow only warm air through the floor vents.
The condition is random in that when I start the vehicle it will give me the warning lights and the adverse operation as listed above, but at random times while driving, usually when cornering, the warning lights will clear, my steering will return, and my AC/Heat functions correctly. This may last for a few minutes and the warning light condition returns with the subsequent adverse conditions.
Before I take this into a shop, sorry I lost the only mechanic I can trust, I wanted to present this scenario and see if you had any suggestions. Is this truly a suspension problem or is this an electrical problem? The only work I have had done on this vehicle is routine LOF which was completed less than 200 miles ago along with an engine flush. Is it possible the tech doing the service jarred a connection loose?
Any suggestions are appreciated.