Diagnostic code for1999 Saturn po141,po404,po440

po0301-6 is not valid

PO128 -- engine coolant low or thermostat not working
P0440 - EVAP system malfunction, gas cap loose - Cat convertors missing from car can cause this
P1189 - Engine Oil Pressure Switch Circuit -- CAT CONVERTORS MISSING FROM CAR can cause this.

Oil pressure switch issue
Coolant temperature sensor issue
EVAP system issue
All different issues, so I suggest seeing a mechanic.

Sadly people don't know that trouble codes only tell the mechanic what to test, not what to replace. And auto parts stores are in the business of selling parts, not giving advice.
Code 135 means there is a problem with the heater inside the o2 sensor for bank one in front of the catalytic converter. Code 141 means the same thing for the o2 sensor after the cat.
Since it is very rare to have two O2 sensors fail at the same time, chances are the problem is lack of power going to the sensors.
The power circuits would need to be checked which requires a shop manual to get the testing procedures and wiring diagrams.

Code 404 is for a problem with the EGR valve and code 307 is for a miss on cylinder 7.
The egr valve would need to be tested, and the spark plug and injector checked out on cylinder 7.

po135 is o2 sencer on drivers side. will be the first one. po300 is random/multiple misfire.po404 is a egr code. po102 mass air flow circuit low input. po440 evap emission control system malfunction

two codes are for an oxygen sensor & the 452 for the evap system

Google OBD2 Systems followed by the code

Code 141 is the O2 (oxygen sensor) gone bad, needs replacing.
Code 440, 442 and 445 are all in the EES (Evaporative Emission System). They are leaks in the PCM (Powertrain Control Module). It tests this system when there is about one fourth tank of gas left.
This system controls fumes from the fuel by storing it in a vapor canister until they can be burned off. This system has several parts in it. You have the solenoid (which is a vent valve and a purge valve), fuel tank, a vapor canister, and you have lines coming from engine vacuum port, going to the vent valve. But you may want to check your gas cap. This is the culprit most of the time. As we take it off and on, it can cause leaks. This is also the cheapest solution. You'll have to clear your code with an OBD scan tool, to see if it was repaired by replacing your gas cap.
Also older vehicles can have a leak around the fuel filler neck where the gas cap attaches to is a seal and it could have gone bad.
A lot of times that seal is leaking around that filler neck. So more likely than not, it is leaking and/or gas cap needs replacing.
A 403, 404,405 are in the EGR System.
401 and 402 are the EGR valve.
You will get these codes because the PCM has sent them. It will send them to test the system as part of a self-diagnostic test and the other reason it sends it is because it wants to monitor the EGR system through everyday, normal operations.
This is what is known as PCM command. It is looking for correct signal of the wires to make sure they are working right from the solenoids in the EGR valve.
There is a problem in the EGR system that needs fixing. Sometimes replacing the EGR valve will fix the problem, but before you go out buying a lot of parts for your car, have a mechanic shop test the EGR system.
Good luck.

p0136 and p0141 are o2 sensors and p0401 is a egr flow and the p0171 means its running lean on low bank 1

go to autozone and have them code check the numbers for you they will give the info from the codes for free if you ask them the wont tell how to fix it but codes will be explained on the print out and its free service