What could cause codes p0171 p1171 p0440 and p0506

[chevyfan]

I have a 2000 S-10 Pick up. 2.2 4 cyls. I'm in California and I need a smog test. Since my service engine light is on, it won't pass. I got the code which indicates the fuel pressure sensor is not working. Someone told me to try a new fuel cap 1st. I did to no avail. I really don't want to drop my fuel tank to replace it. Is there any way around this?
Thanks for your help in advance.

[carriedi]

what was the code number?

[chevyfan]

PO452 twice. The guy at the smog test station looked it up for me. he showed me the computer screen that said fuel pressure sensor.

I just got out from under my truck. I won't be dropping my fuel tank. It looks easier to lift the bed.
Suggestions?

[carriedi]

you're going to need to have a scanner hooked up to your vehicle and check the voltage readings for your fuel tank pressure sensor. the code you have, p0452, is for the computer seeing a voltage reading less than 0.1 volt for a time of 25 seconds. this has to happen two times to set the code. so, reading the scanner will help you see what is happening with the sensor. There are more than just a bad sensor that could be why you have the code. Some times a bad connection at the sensor connector can give a bad reading. also a stuck rollover valve or problem with the purge circuit. driving with a scanner will allow you to see what the sensor is reading and how it is reacting to purge and vacuum testing

it is much easier to drop the tank that to lift the bed, but I have the truck up on a lift over my head. I don't know which would be easier if I had to do it on the ground.

[Jeffrey04]

Hello new member here,
My vehicle is a 2004 Chevy S-10 ZR5 model with a 4.3L engine and automatic transmission with 256,000 miles
For the last several months I have had misfire codes out the wazuu. I have taken the truck to a dealership 3 times for this issue and every time they tell me it's fixed, 30 miles down the road (interstate speeds) SES light will flash at times (especially going up inclines) and eventually the SES light will stay lit.
I have done a lot of research on many different forums and have replaced many parts, which have helped, but it's still not fixed. (I can make a list of everything I've done, if you want.)
So, rather than take it back to the dealer, I would like to have my own diagnostic tool that I can install on my PC so that I can observe exactly what's going on. I've never used a tool like this but I am capable and eager to learn how to use it. I'm a do it yourselfer kind of guy. I would also like this diagnostic tool to have a "re-learn" feature also. I would appreciate any suggestions to point me in the right direction.
Thanks for your time,
Jeffrey
P.S. Today, I am going to pull the spark plugs and check the gaps. Which is .60 per factory specs.

[carriedi]

I don't know of any automotive diagnostic programs like you are talking about. If there was one I would be interested in that. Using a good scanner and being able to understand what it is telling you would be key to diagnosing a problem. (good scanner could run $3000 to $10,000depending on what it has in it. but used could be a lot less.)

Here's the thing, you could be looking all over the computer and hardware parts and overlook a mechanical problem. Always start with the basics.

[MichaelT]

I'm getting all these codes on my 96 2.2l I have replaced plugs wires air and fuel filter checked all evap system components air intake fuel pressure everything's seem to be good but still can't drive it cause it just don't have any power under a load can put it in neutral and it revs fine but don't when it's in gear

[carriedi]

I would look at your O2 sensor and fuel trims first. Use a fuel gauge to measure your fuel pressure. See if it's within spec. From the low idle speed code it doesn't sound like you have a vacuum leak because unmetered air will usually cause a higher idle.

for the codes p0171 and p1171 you should check your fuel pressure. (41 - 47 psi) From your codes, you should look at your fuel trims. (short term and long term) See if the computer is adding fuel to try and make up for the lean readings it's getting from your O2 sensor. Look at the O2 sensor and see if it is switching from above .8 volts to below .2 volts back and forth. Check your injector pulse width to see if the computer is leaving the injector open longer to add fuel to the system.

the evap code p0440 means that your computer see a problem with the ability of your fuel tank system to achieve hold vacuum to the programmed specs it is looking for. So a switch not working correctly, a tank sensor not reading correctly or the system has a leak.

P0506 will be set if your idle is too low. The computer has a desired rpm that it tries to make the engine idle within a certain parameter. The codes sets if the rpm is 60 rpm or more below the parameter it is looking to see. Use your scanner to look at the IAC reading to see what the computer is doing to raise the idle.