e5husmc

Wife's car is showing PO420. Here are the test results:

Vehicle Manufacturer: Chevrolet
Vehicle Calibration ID: 126

Test report:
------------------
MID:$01 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 1 Sensor 1
Max: 0.55022V Min: 0.55022V
Test result value: 0.55022V
PASS
----
MID:$01 TID:$02
Lean to Rich sensor threshold voltage(constant) - O2 Bank 1 Sensor 1
Max: 0.55022V Min: 0.55022V
Test result value: 0.55022V
PASS
----
MID:$01 TID:$03
Low sensor Voltage for switch time calculation - O2 Bank 1 Sensor 1
Max: 0.45018V Min: 0.45018V
Test result value: 0.45018V
PASS
----
MID:$01 TID:$04
High sensor Voltage for switch time calculation - O2 Bank 1 Sensor 1
Max: 0.65026V Min: 0.65026V
Test result value: 0.65026V
PASS
----
MID:$01 TID:$05
Rich to Lean sensor switch time(calculated) - O2 Bank 1 Sensor 1
Max: 99ms Min: 0ms
Test result value: 12ms
PASS
----
MID:$01 TID:$06
Lean to Rich sensor switch time(calculated) - O2 Bank 1 Sensor 1
Max: 120ms Min: 0ms
Test result value: 9ms
PASS
----
MID:$01 TID:$80
- O2 Bank 1 Sensor 1
Max: 65,535Changes Min: 30Changes
Test result value: 278Changes
PASS
----
MID:$01 TID:$81
- O2 Bank 1 Sensor 1
Max: 65,535Changes Min: 30Changes
Test result value: 278Changes
PASS
----
MID:$02 TID:$8a
- O2 Bank 1 Sensor 2
Max: 800Count Min: 0Count
Test result value: 46Count
PASS
----
MID:$02 TID:$8b
- O2 Bank 1 Sensor 2
Max: 1.10068V Min: 0.77531V
Test result value: 0.77665V
PASS
----
MID:$02 TID:$8c
- O2 Bank 1 Sensor 2
Max: 0.10004V Min: 0V
Test result value: 0.08772V
PASS
----
MID:$02 TID:$91
- O2 Bank 1 Sensor 2
Max: 0.45018V Min: 0V
Test result value: 0.40541V
PASS
----
MID:$02 TID:$92
- O2 Bank 1 Sensor 2
Max: 1.10068V Min: 0.55022V
Test result value: 0.55193V
PASS
----
MID:$02 TID:$93
- O2 Bank 1 Sensor 2
Max: 7 Min: 0
Test result value: 0.68
PASS
----
MID:$21 TID:$4d
- Catalyst Monitor Bank 1
Max: 0mHz Min: 4,177mHz
Test result value: 19,744mHz
FAIL
----
MID:$21 TID:$a0
- Catalyst Monitor Bank 1
Max: 0.99939 Min: 0.49971
Test result value: 0.33434
FAIL
----
MID:$3a TID:$c0
- EVAP Monitor (cap off)
Max: 30L Min: 0L
Test result value: 5.836L
PASS
----
MID:$3a TID:$c1
- EVAP Monitor (cap off)
Test incomplete or dependant test failed
--
MID:$3c TID:$c8
- EVAP Monitor (0.040")
Max: 0.64843Ratio Min: 0Ratio
Test result value: 0.00781Ratio
PASS
----
MID:$3c TID:$c9
- EVAP Monitor (0.040")
Max: 0.72655Ratio Min: 0Ratio
Test result value: 0.1289Ratio
PASS
----
MID:$3c TID:$ca
- EVAP Monitor (0.040")
Max: 1Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$3c TID:$cb
- EVAP Monitor (0.040")
Max: 1Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$3d TID:$c4
- EVAP Monitor (0.020")
Max: 6,553.5S Min: 100S
Test result value: 100S
PASS
----
MID:$3d TID:$c5
- EVAP Monitor (0.020")
Max: 2,500Pa Min: -8,000Pa
Test result value: 63Pa
PASS
----
MID:$3d TID:$c6
- EVAP Monitor (0.020")
Max: 60S Min: 0S
Test result value: 2.8S
PASS
----
MID:$3d TID:$c7
- EVAP Monitor (0.020")
Max: 40L Min: 10L
Test result value: 10.009L
PASS
----
MID:$41 TID:$d2
- O2 Heater Monitor Bank 1 - Sensor 1
Max: 8Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$41 TID:$d3
- O2 Heater Monitor Bank 1 - Sensor 1
Max: 2.001 Min: -3
Test result value: 0.182
PASS
----
MID:$42 TID:$d2
- O2 Heater Monitor Bank 1 - Sensor 2
Max: 8Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$42 TID:$d3
- O2 Heater Monitor Bank 1 - Sensor 2
Max: 2.481 Min: -4.199
Test result value: -0.544
PASS
----
MID:$a2 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a2 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a3 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 2Count
PASS
----
MID:$a3 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a4 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 4Count
PASS
----
MID:$a4 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 1Count
PASS
----
MID:$a5 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a5 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$c1 TID:$19
-
Max: 12,292 Min: 10,544
Test result value: 13,280
FAIL
----
MID:$c8 TID:$30
-
Max: 409.70001 Min: 5,641.7002
Test result value: 2,893.1001
FAIL
----
MID:$e1 TID:$19
Manufacturer defined MID -
Max: 41,190 Min: 4,144
Test result value: 6,624
PASS
----
MID:$e1 TID:$8d
Manufacturer defined MID -
Max: 1.25062inch Min: 0.31818inch
Test result value: 0.40504inch
PASS
----

End of report.

Is this a bad O2 sensor or Cat?

Thanks