2003 Honda Element – P1157 AF voltage high after catalytic replacement?

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2003 Honda Element – P1157 AF voltage high after catalytic replacement?

After a thief stole my catalytic converter, I replaced it with an aftermarket one along with an aftermarket downstream sensor. Since then, I’ve been getting a P1157 AF voltage high code. Any fix for this?

Maaz Khan asked on 12 Feb 2025 17:00:01 pm

1 Answer

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Waqar Haider - on 12 Feb 2025 17:07:12 pm

Hello!
I’ve seen this issue a lot after catalytic converter thefts. If the oxygen sensors were damaged o r cut, aftermarket replacements often cause problems. I’ve also come across cases where the sensors were accidentally wired in reverse—plugging the pre-cat sensor into the after-cat harness and vice versa.

The aftermarket catalytic converters seem to work fine as long as they’re CARB certified, but the real problem is usually the wiring o r sensors. If you’re using an aftermarket sensor, I’d recommend switching to an original Honda one and double-checking that the wiring is connected correctly.