O2 sensor faults when throttle is applied?

TMREGER2022

MEMBER
2017 FORD FOCUS
2.0L
4 CYL
2WD
AUTOMATIC
246,000 MILES

I have a 2017 Ford Focus and we’ve had our history, replaced a clutch, catalytic converter, and other things. I truly love this car, but ever since I did my clutch install, Ive been having issues with my oxygen sensor on bank 1. When I run live data, the voltage and current stay consistent, and the status shows no fault. However, the moment I give it gas, it shows a fault and the voltage readings freeze. Could I have damaged the wiring when reinstalling my transmission? Or is there something else that could be the issue? Thanks!

Wednesday, November 12th, 2025 AT 5:29 AM

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
54,208 POSTS

Yes, the sensor is sensitive and could sounds like it is damaged, can I ask if the engine has an exhaust leak in front of the sensor, if so this can cause problems as well. Can I ask what the code number that comes up is? Also, is this the upstream or downstream sensor?

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Thursday, November 13th, 2025 AT 11:00 AM

TMREGER2022

MEMBER
11 POSTS

It’s the upstream sensor, codes that show are P0131, P0132, P1646, P064D. Just installed a brand new OE oxygen sensor, and I made sure to double check the number/fitment. It’s a DY-1199.

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Thursday, November 13th, 2025 AT 1:02 PM

TMREGER2022

MEMBER
11 POSTS

I think I may have figured it out. The connector was pulled over the harness, putting strain on the wires. I rearranged the wiring, making sure there were no snags or twists, and it seems to be running fine! Live data displays no faults and there were no DTCs when I ran an OBD check, so I think we’re in good shape! Thanks for your help! You helped me before with the clutch install, and I did have to completely replace the clutch, but since then, it’s been a great running car! Youve been a great help with keeping this car going! Thank you again, and take care!

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Friday, November 14th, 2025 AT 10:42 AM

KEN L

MASTER CERTIFIED MECHANIC
54,208 POSTS

Yes! Nice work, glad you could get it fixed, thanks for letting us know.

P0131 - O2 Sensor Bank 1 Sensor 1 Low Voltage

P0132 - O2 Sensor Bank 1 Sensor 1 High Voltage

P1646 - HO2S Heater Control Circuit

P064D - Internal Control Module O2 Processor Performance

If the codes come back I would replace the sensor FYI :) Please use 2CarPros anytime we are here to help.

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Saturday, November 15th, 2025 AT 9:17 AM