Can a new CAT cause o2 sensor codes on the old sensors?

[GeoTracker]

CAT recall: Second LH CAT replacement followed within a week with o2 sensor codes on the same CAT. Should sensors be replaced when you replace a low mileage CAT under warranty recall?

Dealer replaced the bad bank 2, #1 o2 sensor but still had codes. They replaced the sensor a second time with no resulting codes. Taking it home today, sensor covered by ESP Warranty. The codes were: P2240 “O2 Sensor Positive Current Control Circuit/Open Bank 2 Sensor 1” and P2629 "O2 Sensor Pumping Current Trim Circuit". Glad to have it back. Still a great ride!

 

[FordFlintrock]

CAT recall: Second LH CAT replacement followed within a week with o2 sensor codes on the same CAT. Should sensors be replaced when you replace a low mileage CAT under warranty recall?

No, unless TSB requires

Dealer replaced the bad bank 2, #1 o2 sensor but still had codes. They replaced the sensor a second time with no resulting codes. Taking it home today, sensor covered by ESP Warranty. The codes were: P2240 “O2 Sensor Positive Current Control Circuit/Open Bank 2 Sensor 1” and P2629 "O2 Sensor Pumping Current Trim Circuit". Glad to have it back. Still a great ride!

Aside from what looks to be an exhaust leak let us take a methodical approach to the O2 sensor codes
Never a problem prior the cat replacement
Two sensors same problem
Two codes and one apparent circuit in common between both for an "open"
Cat replacement requires sensor harness connector removal
Due to heat cycles the sensor connector can be difficult to separate requiring some degree of pulling on wires of connector
I would first be looking at the harness side of the six wire connector for that wire(s) to connector being damaged during separation

P2240 - Ford Diagnostic Trouble Code (DTC) Definition, Causes and Diagnosis

P2240 Ford Diagnostic Trouble Code (DTC) Definition, Causes and Diagnosis

www.dtcdecode.com

P2629 - Ford Diagnostic Trouble Code (DTC) Definition, Causes and Diagnosis

P2629 Ford Diagnostic Trouble Code (DTC) Definition, Causes and Diagnosis

www.dtcdecode.com

 

[GeoTracker]

Thank you for the reply, it was very helpful. I, like many forum members, am good at DIY as I like to make sure that the correct repairs are made the first time. However, with a factory recall, it is always best to go to the dealer and often takes several trips back to resolve the issue.

In this case the first CAT replacement resulted in an exhaust leak on the back side as seen in the photo and could be heard from inside the vehicle until it warmed up. I just wanted the leak fixed from the failed installation, but got another replacement CAT. Then within several days got the o2 sensor alerts and back to the dealer for the third time. This time they replace the o2 sensor twice before the codes cleared. One CAT charged to recall, one CAT charged to emissions warranty and the sensor charged to ESP Warranty. SO GLAD IT WAS NOT ONE OF MY DIY JOBS. I did notice that most of the service tech's are about the age of my grandson. Not that that in its self is bad, but experience is always helpful. IT TOOK ONE WEEK TO REPLACE THE O2 SENSOR. Total time for two CATS and Sensor three weeks, listed two techs on the job. I bet the next CAT and sensor replacement on a ST will be a lot faster from the learning experience on mine.

 

[FordFlintrock]

Three weeks loss of use on the vehicle is way too long and your experience typifies areas that need addressing by Ford.

Through Ford training years ago we were taught to 1)Verify the problem 2)Identify the problem 3)Repair the problem 4)Verify the repair
I would bet the kid heard that exhaust leak when first started or should have been found when the car went back up on the lift taking the 90 seconds checking for exhaust leaks.
A slight modification to the exhaust band clamp which I would have done first time around would mean another happy customer on the road without having to come back saving Ford $$$.