I'm not understanding the code of 20, your 1997 Saturn has an OBDII computer. you need a code reader to get engine codes. you cannot pull codes manually by shorting terminals A-B anymore. every one of your engine codes is atleast 3 digits, and should start with P. for example: a faulty oxygen sensor with no responce will show a code of P0134, or a EGR with insufficient flow will show a code of P0401.
Answer
My code book shows that an OBDII code of P0020 is a camsharft position actuator circuit bank 2. you have a sensor problem or your cam chain has stretched beyond the tensioner's ability to remove slack. I was getting camshaft position errors and had to replace the cam chain and tensioner.
Problems with the oxygen sensors are quite likely to cause emissions test problems. The car computer cannot properly adjust the air/fuel mixture to regulate the emissions.
Varies, a couple of weeks should be enough.
As far as I know there is 2 02 sensors if you look into the wheel well with the tires turned you can see them just to the back of the manifolds. They should be pointing straight up. I just replaced the o2 sensors in my 98 and there was 2. It may depend on if you have standard or CA/MA emissions. My truck has one with standard emissions. The same truck in CA or MA has two. 95 f150 5.8
I can assure you that the O2 sensors will not prevent the enigne from starting, even if they are disconnected or removed. Something else is the culprit.
They are replaced when they go bad.
No you cannot, It is controled by the computor-- Emissions sensors. What emission sensors,where would they be located?
Most 4.0L engines with federal emissions have two oxygen sensors located on the exhaust pipe before the muffler. One sensor is mounted before the catalyst (upstream) and one is mounted after the catalyst (downstream). Most 4.0L engines with California emissions have four oxygen sensors. These are mounted in the exhaust manifold area. Two are upstream and two are downstream. There is an emissions label under the hood of the vehicle that identifies the emissions type.
If the oxygen sensors for the 1991 Chevy 4.3 is running rich when it is warmed up it is best to have the sensors replaced. Once the sensors are replaced this should resolve the issue.
All sensors, air pump, and EGR
There are about 7 sensors on the engine that are to reduce emissions.
Have you had your 4 oxygen sensors replaced? It turns out when they replaced my oxygen sensors, they were after market parts so the service engine light did not come and gave codes even though they were replaced.
It will have two or four depending on the emissions package.