2016 f150 3.5ecoboost L - Anyone know which sensor the PO430 sensor light is connected to? Took my truck to the dealer and they’re telling me that the light needs to be on before they will fix the sensor or change the catalyst. I’m very frustrated as I took it to two different mechanics and they all told me the same thing.

 

P0430- Catalyst System Efficiency Below Threshold Bank-2 (left side/driver's side)

 

Thoughts on what should get replaced? I guess there are 4 sensors. They don’t know what sensor to replace which is mind boggling.

 

how long have you been getting this code?

And, did you have a misfire condition, or some problem that caused this?

If you did have a problem (ex: misfire) that has been fixed, I would keep clearing the code for a while and see if 430 code might stop.

 

Replacing the sensors may not necessarily fix the issue, as there are a lot of possibilities for this code:

• Damaged oxygen sensor
• Damaged oxygen sensor wires and/or incorrectly connected
• Exhaust leaks
• Damaged catalytic converter
• Oil contamination
• Leaky/stuck/clogged fuel injector
• Cylinder misfiring
• EVAP purge valve stuck open
• Damaged turbo

 

Can a possible water pump leak damage the catalyst and have the PO430 check engine light appear and disappear ?

 

Theoretically speaking, yes it's possible for coolant to leak into the combustion chamber of the cylinder and clog the catalytic converter. Although I'm not aware of how common this issue is with 3.5 ecoboosts, however, if by some chance that is the case in your situation, P0430 might be the least of your problems.

Your best bet would be to inspect the exhaust system, looking for any possible exhaust leaks and any damage to the catalytic converters, then check the wiring on the oxygen sensors. Depending on your mileage on the truck, you might want to replace the O2 sensors to see if that fixes the issues. And/or possible replace the catalytic converters, but those are expensive and you might even have to wait a while if shops in your area don't have them in stock.

 

How would a leaking water pump allow coolant into combustion chamber (note: I do not know economists)?

 

You're right, not a water pump itself, but a crack in the engine block could allow coolant to leak into the combustion chamber.

 

It was checked 3 times from 3 different mechanics and the final mechanic was the dealer. Of course, the light goes off before I head back to the dealer. Go figure