Check engine light and code P2A03

PRSMI

MEMBER
2006 CADILLAC DEVILLE DTS
AUTOMATIC
109,872 MILES

I'm getting code P2A03 and the check engine light comes on for a few days then goes off. I was told I needed to replace the upstream 02 sensor. They didn't say whether it's the front or rear. Is this the right fix for these code? If so which should I replace?

Sunday, March 15th, 2020 AT 10:12 PM

3 Replies

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Could you please double check the Direct Trouble Code[DTC] for us. It should be a letter followed by 4 numbers. The upstream O2 sensor is the one closest to the engine, not the one that's after the catalytic converter. Please get back to us with the DTC and we can go from there.

Thanks,
Alex
2CarPros

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Monday, March 16th, 2020 AT 3:24 AM

PRSMI

MEMBER
2 POSTS

The trouble code was P2A03. "02 sensor circuit range/performance bank 2 sensor 1".

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Monday, March 16th, 2020 AT 9:20 AM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello again,

Okay, I stand corrected. It appears that Cadillac has taken a multitude of DTC's and rolled them into this one new DTC numbering system, exclusively for them. In the diagrams down below I have included the diagnostic troubleshooting guide for DTC P2A03 for your vehicle. Please go through this guide and get back to us with what you find out.

Thanks,
Alex
2CarPros

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