I don't know why it didn't register in my mind that you are in California. It says right there on your signature Los Angeles.
When I first began looking into checking for a fault code, I read a Bosch injection manual that gave a fault code chart. I found out here at mshop that this was only for California cars, Federal cars have a few fault codes that are indicated by duty cycle.
My manual tells me how to read fault codes on the California car. It is done by removing the fuse on the fuel pump relay and counting the blips at the diagnostic socket. To adjust the lambda, you PROBABLY have to use the current method, but I'm not at all sure. You need a manual for a Cal. car.
I'm sorry I didn't pick up on this earlier to keep you from chasing your tail on this.