Please point me in the right direction

[masanders]

HI. I'm currently a Ranger owner, but my wife is an 07 escape owner. I'm working on registering with an escape forum but it's taking forever. The Escape is getting an p0420 code: Catalyst System efficiency below threshold bank 1. I've ran a live data and a freeze frame and have a report. I just got this scantool and am not sure what I'm reading. Can someone look over the data for me and tell me if it indicates that the catalytic converter is bad?

 

[RonD]

What size engine is in the Escape?

All systems work like this

Bank 1 sensor 1 is the passenger side O2 sensor closest to the engine, called the Upstream O2 sensor

Bank 2 sensor 1 is the drivers side Upstream O2 sensor

This is for V6 and V8 engines

On a 4 Cylinder engine there is just Bank 1 sensor 1, regardless of which side the exhaust is on, that's the only Upstream O2 sensor

The Upstream O2 sensors are used by the computer to adjust Fuel Trim
0 Fuel trim is the target
-5 to +5 trim is OK, this is Short Term Fuel Trim

After 1995 Rear O2 sensors were added to test if Cat Converters were working, this is called a Downstream O2 sensor
On a single exhaust vehicle Bank 1 sensor 2 is the Downstream O2 sensor

Dual exhaust will have Bank 2 sensor 2, a second Downstream O2 sensor

There are two kinds of O2 sensors, narrow band and wide band
Narrow band is what has been used since there were O2 sensor
It has a voltage range of .1volt to .9volt
.9 is Rich, low oxygen level
.1 is Lean, high oxygen level

Because a Cat Converter burns off hydrocarbons the Downstream O2 sensor should show low voltage .1, .2 volts, Lean, cleaner exhaust

Upstream O2 should be .3 to .6 volts

Yours look like narrow band O2s but Bank 2 is way out, so is this a 4cylinder engine?

Wide band O2s are 0 to 5volts

 

[masanders]

Sorry about that RonD... It's a 3.0L V6

 

[masanders]

Three years later I’ve got the same issue again.
2007 Ford Escape, 3.0 V6
P0420
We had the cats replaced in 2017 and now the code is back.
This is a screenshot of the voltage:

What am I missing here? Is there something else going on that’s fouling up the cats?
Any help is appreciated!

 

[RonD]

You have Dual exhaust?

Bank 1 is passenger side, or rear, sensor 2 is the one behind(after) the Cats on that bank, it should read .7-.8 volts so looks just fine
Bank 1 sensor 1 looks OK as well

Bank 2(drivers side or front) sensor 2 looks wrong but ONLY if you have dual exhaust, and that should be code P0430
Bank 2 sensor 1 is also Lean, which would also be a different code, P0174

 

[masanders]

You have Dual exhaust?

No sir. The Escape is a V6 with 2 manifold/cats going to a single out.

 

[RonD]

Then there is no B2S2, bank 2 sensor 2, so ignore that

How many miles in the upstream O2 sensors?
The sensor 1's
Bank 2 S1 could just be worn out, out of chemicals, which causes Lean voltage
They last about 125k miles
But best to change both upstream sensors at the same time

 

[masanders]

All O2 sensors are three years old. When we originally had to replace the two manifold cat combos, we had the O2 sensors replaced as well. I don’t know exact mileage on them, but they are easily under 25k.