1995 S420 – went to replace the oxygen sensor and found the old unit plug into the main wiring harness had fused from an overheated catalytic converter, preventing old unit from being unplugged from the harness. Any suggestions on how to fix this? Much thanks for any ideas.

You can check the EPC, or ask dealer, if there is a repair harness. Otherwise, Check on a universal sensor, which I think comes with a connector you splice up to your existing wires.

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