Dtc p0511 this code pops up after you clear it as stored and pending

redux1: 2009 2.2 L Ecotec LAP I4 (cal, fed or canada?) bingo
no country stated, and My guess did not buy the full walker front dual cat pipe or a new B1S2 sensor firs.

so no other DTC errors.??????
the p420 is the cat test but the Two Oxygen 02 sensor front and rear of the cat must be good. or p420 lies. ( the ECU likes your front B1S1 sensor but is S2 , replaced?

and no other DTC errors, like P03xx codes, of any kind.
or fueling codes.DTC.
that is correct exhaust leaks there, do cause 02 sensor to lie. as in read wrong even good ones.
use a real scan tool not some $20 code reader only


and see all chevy factory codes P1xxx , P2xxx and up.
never use cheap tools that only see P0xxx federal codes only.
they are no good.


using any real tool , check live DTC,
and stored DTC and check
all PENDING DTC
and let all MONITORS run out first, for sure all 02 tests .(all)
and do 3 driving cycles so you see them ALL..
(answers are USA spec cars, OBD2) and only real scan tools.

simple answer is bad CAT, but why not have real shop test the cat first. they have the tools , a real ASE shop, I PROMISE YOU.
one is the thermal test. (IR gun test) (ok done and looks ok)
and 2nd is 4gas tester to see if ,input gasses and output are correct at CAT>
a $3000 tool on up.

4 gas analyzer measures Carbon Monoxide (CO), Carbon Dioxide (CO2), Fuel Dependent Hydro Carbons (HC), and Oxygen (O2)<< a real shop does this to not guess what is wrong.
input and outputs checked, end to end.


2009 2.2 L Ecotec LAP I4 << told now. later. thanks !

Is the check engine light on ? Any DTC'S - diagnostic trouble codes stored ? If any of these are true , light on or code's stored monitors will not set . Too set all monitors you do a drive cycle . A very specific way of driving your vehicle .

http://www.lyberty.com/car/drive-cycle.html

check and test the crankshaft position sensor and also the camshaft position sensor. Have a local autoparts store scan the dtc or diagnostic troubleshooting codes. this will you give yo a better idea of whats causing the issue. Also clear all dtc's and drive vehicle until check engine light comes back on. recheck codes. but i will almost bet the bank its going to be one of those sensors. also oil leaks will do a number on the wiring connectors. possibly a simple cleaning of the wiring connectors will solve the issue too

Could be a wiring problem or throttle position sensor or the DC motor that controls the throttle position. P0511 Toyota Idle Control System Malfunction

Pending codes and current codes are basically the same. Pending codes are for a problem that is still indicated to be a problem,but hasn't been cleared. Current codes are codes that are indicated for the current drive cycle. Usually will both be the same code if problem still exists and hasn't been cleared without repair.

The pd means the code is pending, (or intermittent, stored code). Here is what the code means----this DTC indicates that an evap system purge flow was seen by the vehicles PCM ( computer ) during a non purge condition.
Simply put the EVAP purge valve was open when it should not have been. Likely a mechanical failure of the purge valve.
This repair should not be too expensive .

Codes

Print
Stored fault codes may be erased from memory at any time by removing power from the VCM for at least 30 seconds. It may be necessary to clear stored codes during diagnosis to check for any recurrence during a test drive, but the stored codes must be written down when retrieved. The codes may still be required for subsequent troubleshooting. Whenever a repair is complete, the stored codes must be erased and the vehicle test driven to confirm correct operation and repair.

WARNING The ignition switch must be OFF any time power is disconnected or restored to the VCM. Severe damage may result if this precaution is not observed.
Depending on the electrical distribution of the particular vehicle, power to the VCM may be disconnected by removing the VCM fuse in the fusebox, disconnecting the in-line fuse holder near the positive battery terminal or disconnecting the VCM power lead at the battery terminal. Disconnecting the negative battery cable to clear codes is not recommended as this will also clear other memory data in the vehicle such as radio presets.
The following are the codes for the 1994-95 models with the OBD I and OBD II systems.
See Figure 1 through 6

Fig. Fig. 1: DTC chart for 1994 ECM models

Fig. Fig. 2: DTC chart for 1994 PCM models

Fig. Fig. 3: DTC chart for 1994-95 VCM models

Fig. Fig. 4: DTC chart for 1995 PCM models

Fig. Fig. 5: DTC chart for 1995 VCM-A models

DTC P0463 - Fuel gauge sender unit circuit high input
• The PCM monitors the fuel tank level and input voltage from the fuel gauge sender unit when the engine is running. If the input voltage is more than 2.5 V and fuel tank level is empty, the PCM determines that the fuel gauge sender unit circuit input voltage is high.

Diagnostic support note
• This is a continuous monitor (CCM).
• The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
• PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
• FREEZE FRAME DATA is available.
• The DTC is stored in the PCM memory.

Possible cause:
• Fuel gauge sender unit malfunction
• Instrument cluster malfunction
• PCM malfunction

Feel free to contact us if need additional details. Good luck.

Both of these monitors won't run until the oxygen sensor monitor has run. The oxygen sensor monitor won't run if an Engine Coolant Temperature (ECT) sensor Diagnostic Trouble Code (DTC) is stored. So, did you replace the errant coolant temp sensor? I take it you did and reset the codes. But you need to check the codes again and see if there are any that returned or are pending. A pending misfire code will not allow the oxygen sensor monitor to run. (Pending codes will not turn on the check engine light.)

This information is from Haynes Techbook "OBD-II" (No. 10206) Chapter 6, p. 14-16
(Highly recommended reading!)

P0146 pd means pending code
Pending codes and DTCs? Posted on November 12, 2010 by fcrmaster
When reading codes from your vehicle the fault code reader may show them as pending codes or normal Diagnostic Trouble Codes (DTC).
Pending codes (also known as continuous monitor codes) will be registered when an intermittent fault occurs. If that fault does not happen again after x number of start/stop cycles, the ECU will erase the code from memory. If the fault is persistent it becomes a DTC.
If you have read pending codes it is advisable to check the codes again after a week or so. If there is no apparent problem with the vehicle it is safe to erase the codes too and check back. But always make a note of any fault codes with the date and mileage of a vehicle.
If the codes read include a DTC then you need to investigate further. This you can either do yourself or advise your garage. If, again, you don't see an apparent problem (depending n the severity of the code) with the vehicle you can note the codes down and erase them. Then check again after a week or a few days depending on how often the vehicle gets used. If a repair has been made (previous owner) the DTC may just not have been reset after the repair.
The other numbers behind the code 01/06 , 02/06, 03/06 , 05/06 ,04/06 These don't mean anything . cheap code reader .
DTC P0140 HO2S Circuit Insufficient Activity Sensor 2
DTC P0146 HO2S Circuit Insufficient Activity Bank 1 Sensor 3
DTC P0171 Fuel Trim System Lean Bank 1
DTC P0174 Fuel Trim System Lean Bank 2
Sorry but this is something you should take to a qualified repair shop that has a diagnostic tool that can view sensor scan data.
Causes of lean condition trouble codes P0171 P0174 GM 5 3L