2 po442 codes showing up on my 2003 buick century

no its an evap leak small can be possible bad gas cap the following link can assist
https://www.obd-codes.com/p0442

no nothing to do with transmission ---its an evap code small leak detected this is the usual check gas cap that its on and tight or replace because seal is shot but the following link explains the other problems with assistance in helping repair problem
http://www.obd-codes.com/p0442

this relates to a slight leak of fuel vapour to atmosphere from the EVAP system , to check undo and refit gas tank cap and clear code , then drive for a day and rescan for code , if reappears then the EVAP system will need inspecting for leakage

PO442 indicates a fuel vapor leak in the EVAP control system. It means a very small leak has been detected. In fact, the leak can be from a hole as small as 0.04" in diameter. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.A code P0442 most likely means one or more of the following has happened:

• A loose or improperly affixed gas cap
• A non-conforming gas cap (i.e. not factory/original brand)
• A small leak/hole in a fuel vapor hose/tube
• Other small leak in EVAP system
• Faulty vent o-ring seal

With a P0442, the most common repair is to:

• Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
• Otherwise, replace the gas cap, or
• Inspect the EVAP system for cuts/holes in tubes/hoses

P0463 Fuel Level Sensor Circuit High Voltage

If you are getting a code saying that there is a problem with your evaporative emission control system, it is often related to the gas cap. In many cases replacing the gas cap will fix the problem.

P0442 OBD-II Trouble Code - Evaporative Emission Control System Leak Detected (small leak)

What does that mean?
This indicates a fuel vapor leak in the EVAP control system. It means a very small leak has been detected. In fact, the leak can be from a hole as small as 0.04" in diameter. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.


Symptoms
You likely won't notice any drivability problems.


Causes
A code P0442 most likely means one or more of the following has happened:
* A loose or improperly affixed gas cap
* A non-conforming gas cap (i.e. not factory/original brand)
* A small leak/hole in a fuel vapor hose/tube
* Other small leak in EVAP system
* Faulty vent o-ring seal


Possible Solutions
With a P0442, the most common repair is to:
* Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
* Otherwise, replace the gas cap, or
* Inspect the EVAP system for cuts/holes in tubes/hoses




Fig. EVAP vent solenoid (2) on 3.1L, 3.4L, 3.5L & 3.8L, showing the connector (1) and vapor line (2)




Fig. EVAP canister purge solenoid location on 3.1L & 3.4L




Fig. EVAP purge solenoid valve (3) location on 3.5L




Hope this help, good luck.

P0401 sets when EGR flow test runs and fails. EGR may be moving too slow or not at all. May be a bad connection.
P0442 sets when vacuum decay test indicates small leak in the EVAP system detected during diagnostic test. Check for a loose or defective gas-cap. If the cap is fine it may be a false code or could be related to another EVAP component.

PO442 means you have a small leak in your EVAP system. Most common cause is a bad gas cap, replace the gas cap with a factory gas cap,after market fail or does not conform to the OEM EVAP system. Other cause would be small leaks in the EVAP vacuum lines. P0445 is also related to the EVAP system and has detected a large leak in the system. Start with the gas cap as mentioned above. P1685 Is an issue with the ignition not recognizing the ignition keys and the car's ignition immobilizer my activate leaving the car not being able to start. That's going to have to be a Dealer repair. Good luck and hope this helps.

Usually the source of the leak is the gas cap (either loose or defective) but if that doesn't apply to your issue then the canister is next to the gas tank.

P0442 EVAP System Small Leak (0.040") Detected


EVAP fuel tank or canister vapor hoses leaking or damaged
EVAP system component leaking, damaged or has failed
Fuel tank cap is loose, or the cap release pressure is incorrect
Leak detection pump damaged or leaking

You can try the gas cap first, if that does not help you will need to take it to a repair shop, Small leaks are very hard to find. If you want to know what turns on the light here it is.

Cold engine startup (ECT sensor from 40-90�F and within 10�F of the BTS input at startup), fuel level more than 1/2 full, engine running, EVAP leak test "on", and the PCM detected a leak greater than 0.040� but less than 0.080" somewhere in the system.
This code sets in 2 Trip(s).