rjnonnie, thanks for the removal instructions. I was able to remove the fastener from above with large needle nose pliers, but the entire pin and socket came out together. I probably could have reused it, but instead I used a small 10-32 nylon screw, washer, and nut to fasten it. I have the screw "upside down" to make it much easier to hold the nut on top while turning the pan head screw from below. It worked great and I if ever have to replace the cap again it will be much easier.

Hopefully this will solve the "Check Engine Electronics" problem. I'll post again once I know the results.

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Dave

1998 E320
2001 SLK320
2000 Lexus RX300