Why the problem with 02 sensor slow during catalyst monitor

The diagnostic trouble code (DTC) P0420 "Catalyst System Efficiency Below Threshold" is one possible outcome following the Catalytic Converter Monitor (test). This monitor is one of the last tests to be performed by the powertrain control module (PCM) because other failures in the system could compromise this test's result. Catalyst efficiency is tested by observing the oxygen sensor signals both before and after the catalyst. Before the catalyst, the signal should appear as a sine wave as it switches back and forth between rich (0.9 volts) and lean (0.1 volts). After the catalyst, the signal should be flat-lined on the rich side (about 0.7 volts). This is because a healthy catalyst will store oxygen and therefore remove the "lean" portion of the signal/waveform. If the signal after the catalyst still appears as a sine wave, the PCM concludes that the catalyst can no longer store oxygen and should therefore be replaced. In your specific scenario where a downstream (post-cat) O2 sensor was just replaced, I would theorize that this sensor had failed and was flat-lined. Then when it was replaced two things happened: 1.) the oxygen sensor began to work properly which allowed the oxygen sensor monitor (test) to complete, and 2.) the catalyst monitor then ran and used the new (accurate) sensor data to determine that the catalyst efficiency was below threshold. You can read more here: https://www.yourmechanic.com/article/p0420-obd-ii-trouble-code-catalyst-system-efficiency-below-threshold-bank-1-by-jamahl-walker

The code reads as..
"Slow Switching O2 Sensor Bank two Sensor one During catalyst monitoring"
You may have a faulty oxygen sensor on you exhaust system. If you have a V6 or V8 engine you will have sensors on both exhaust pipes.
Some engine error codes don't automatically clear. Certain codes need to be plugged into an OBD2 diagnostic scanner to delete it.

Definition of Diagnostic Trouble Code P1041 Saab: Injector Cylinder 4 Shorting To Ground

There is no definition for DTC P1047

CodeDescription P1192 Inlet Air Temp. Circuit Low P1193 Inlet Air Temp. Circuit High P1195 1/1 O2 Sensor Slow During Catalyst Monitor P1196 2/1 O2 Sensor Slow During Catalyst Monitor P1197 1/2 O2 Sensor Slow During Catalyst Monitor P1198 Radiator Temperature Sensor Volts Too High P1199 Radiator Temperature Sensor Volts Too Low P1281 Engine Is Cold Too Long P1282 Fuel Pump Relay Control Circuit P1283 Idle Select Signal Invalid P1284 Fuel Injection Pump Battery Voltage Out Of Range P1285 Fuel Injection Pump Controller Always On P1286 Accelerator Pedal Position Sensor Supply Voltage Too High P1287 Fuel Injection Pump Controller Supply Voltage Low P1288 Intake Manifold Short Runner Solenoid Circuit P1289 Manifold Tune Valve Solenoid Circuit P1290 CNG Fuel Pressure Too High P1291 No Temp Rise Seen From Fuel Heaters P1292 CNG Pressure Sensor Voltage Too High P1293 CNG Pressure Sensor Voltage Too Low P1294 Target Idle Not Reached P1295 No 5 Volts To TP Sensor P1296 No 5 Volts To MAP Sensor P1297 No Change in MAP From Start To Run P1298 Lean Operation At wide Open Throttle P1299 Vacuum Leak Found (IAC Fully Seated) P1388 Auto Shutdown (ASD) Relay Control Circuit P1389 No Auto Shutdown (ASD) Relay Output Voltage At PCM P1390 Timing Belt Skipped One Tooth or More P1391 Intermittent Loss of CMP or CKP P1398 Mis-Fire Adapter Numerator at Limit P1399 Wait To Start Lamp Circuit P1403 No 5 Volts To EGR Sensor P1475 Aux. 5 Volt Output Too High P1476 Too Little Secondary Air P1477 Too Much Secondary Air P1478 Battery Temp Sensor Volts Out of Limit P1479 Transmission Fan Relay Circuit P1480 PCV Solenoid Valve P1482 Catalyst Temperature Sensor Circuit Shorted Low P1483 Catalyst Temperature Sensor Circuit Shorted High P1484 Catalytic Converter Overheat Detected P1485 Air Injection Solenoid Circuit P1486 Evap Leak Monitor Pinched Hose P1487 Hi Speed Rad Fan CTRL Relay Circuit P1488 Auxiliary 5 Volt Supply Output Too Low P1489 High Speed Fan CTRL Relay Circuit P1490 Low Speed Fan CTRL Relay Circuit P1491 Rad Fan Control Relay Circuit P1492 Battery Temperature Sensor Voltage Too High P1493 Battery Temperature Sensor Voltage Too Low P1494 Leak Detection Pump Switch or Mechanical Fault P1495 Leak Detection Pump Solenoid Circuit P1496 5 Volt Supply Output Too Low P1498 High speed Rad Fan Ground CTRL Rly Circuit P1594 Charging System Voltage Too High P1595 Speed Control Solenoid Circuits P1596 Speed Control Switch Always High P1597 Speed Control Switch Always Low P1598 A/C Pressure Sensor Volts Too High P1599 A/C Pressure Sensor Volts Too Low P1602 PCM Not Programmed P1680 Clutch Released Switch Circuit P1681 No I/P Cluster CCD/J1850 Messages Received P1682 Charging System Voltage Too Low P1683 Speed Control Power Relay Or Speed Control 12 Volt Driver Circuit P1684 Battery Disconnected Within Last 50 Starts P1685 Skim Invalid Key P1686 No SKIM Bus Message Received P1687 No Cluster Bus Message P1688 Internal Fuel Injection Pump Controller Failure P1689 No Communication Between ECM & Injection Pump Module P1690 Fuel injection pump CKP Sensor Does Not Agree With ECM CKP Sensor P1691 Fuel Injection Pump Controller Calibration Failure P1693 DTC Detected In ECM Or PCM P1694 No CCD Messages Received From ECM P1695 No CCD/J185O Message From BCM P1696 PCM Failure EEPROM Write Denied P1697 PCM Failure SRI Mile Not Stored P1698 No CCD Messages Received From PCM P1719 Skip Shift Solenoid Circuit P1740 TCC Or OD Solenoid Performance P1756 Governor Pressure Not Equal To Target At 15?20 PSI P1757 Governor Pressure Above 3 PSI When Request Is 0 PSI P1762 Governor Pressure Sensor Offset Improper Voltage P1763 Governor Pressure Sensor Voltage Too High P1764 Governor Pressure Sensor Voltage Too Low P1765 Trans 12 Volt Supply Relay Control Circuit P1899 Park/Neutral Position Switch Stuck In Park or In Gear

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O2 Emission Monitors & Evap Monitor-- are two
different systems

Get ALL your OBD Codes & work them one at a time,
& DO NOT Clear any data with code reader or removing
battery cable, or the monitors ALL have to run again

The heater may work in the sensor, but the sensor doesn't
switch fast enough or is worn out & the front sensors get
replaced at 100,000, before they fail or slow down

The Evap Codes will be needed, to work on that issue
That monitor runs last & only every few days

IF--- you had professional scan tool software, you would see
11 monitors & maybe 8 that run on your vehicle

There will be at least 2 for the O2,one for cylinder misfire,
one for evap, one for egr,& three others

rear 02 sensor defective or (s2 bank one or two ) drive cycle has not reset the monitor yet,, Catalyst is the longest to reset usually

Get the codes,diagnose using the codes

Need trouble charts & component test

Not replacing parts & hoping for results

Let's see if I got this right.The vehicle can't be driven because of legal issues with the emissions test, and it has to be driven 200 miles before it can be tested. Talk about your catch 22. Jack that thing up, put it on jack stands, fire it up, put it in gear, and watch the miles add up.

DTC P0420: Catalyst System Efficiency Below Threashold (Bank 1)

The ECM uses sensors mounted before and after the three-way catalyst (TWC) to monitor its efficiency. The first sensor, and Air Fuel ratio (A/F) sensor, sends pre-catalyst A/F ratio information to the ECM. The second sensor, a heated oxygen sensor (O2S), sends post-catalyst information to the ECM. The ECM compares these two signals to judge the efficiency of the catalyst and the catalyst's ability to store oxygen. During normal operation, the TWC stores and releases oxygen as needed. The capacity to store oxygen results in a low variation in the post-TWC exhaust stream as shown below.
If the catalyst is functioning normally, the waveform of the heated oxygen sensor slowly switches between RICH and LEAN. If the catalyst is deteriorated, the waveform will alternate frequently between RICH and LEAN. As the catalyst efficiency degrades, its ability to store oxygen is reduced and the catalyst output becomes more variable. When running the monitor, the ECM compares sensor 1 signals (A/F sensor) over a specific amount of time to determine catalyst efficiency. The ECM begins by calculating the signal length for both sensors (for the rear oxygen sensor, the ECM uses the output voltage signal length). If the oxygen sensor output voltage signal length is greater than the threshold (threshold is calculated based on the A/F sensor signal length), the ECM concludes that the catalyst is malfunctioning. The ECM will turn on the MIL and a DTC will be set.
Hope this helps :)

possible causes: catalyst monitor, misfire, evaporative system, egr system, fuel system, heated catalyst, 02 sensor, 02 sensor heater air con system refrigerant.

If you have an exhaust leak before or after the catalytic convertor, then the response of the of the sensor could be slowed.

An excerpt from Wikipedia:
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Location of the probe in a system
The probe is typically screwed into a tapped hole in the exhaust, located after the branch manifold of the exhaust system combines, and before the catalytic converter. New vehicles are required to have a sensor before and after the exhaust catalyst to meet U.S. regulations requiring that all emissions components be monitored for failure. Pre and post-catalyst signals are monitored to determine catalyst efficiency. Additionally, some catalyst systems require brief cycles of lean (oxygen-containing) gas to load the catalyst and promote additional oxidation reduction of undesirable exhaust components.
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It's a good article about the two-sensor system and oxygen sensors in general and is available here:

http://en.wikipedia.org/wiki/Oxygen_sensor