RDK Bypass
1990 928 S4

July 23, 2000

My Tire Pressure warning light was constantly coming on. I had to inflate the rear tires to over 44 lbs. to get the silly light to stay off. While doing my pre-race inspection, Marc Thomas commented that my rear tires were wearing too fast in the middle, a sign of over inflation. I told him about the Tire Pressure warning and he suggested I bypass the RDK computer. The RDK warning system was installed on the 928 from 1990 to 1993.

I had read that the RDK computer remembers it prior setting, so I inflated the tires to 44 lbs. and checked to make sure the Tire Pressure warning light was off. I then disconnected the battery.

The RDK computer is located on the driver's side, under the dash. Marc had made up a bypass wire for me (for sale at DEVEK for $15 including instructions). I would be easy enough to make, you just have to get the right male plug ends, but for $15 it wasn't worth a trip to Radio Shack and figuring out which plugs I needed.

I stuck my head under the dash and found the plug. I had to release the clip on the wire side and pivot the plug out. I then installed the bypass wire in plugs 2 and 13. I then taped up the exposed end, and used nylon ties to secure it in place.

I then reconnected the battery and checked the Tire Pressure warning light. I was still off. I then deflated the rear tires to 38 lbs. and rechecked the warning light. It was still off.

The whole process took about 15 minutes.

The RDK Bypass wire installed

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Copyright 2000, George A Suennen
written: 07/23/00
rev: 09/05/00