Codes P0171 and P0420

Hello,

It sounds to me like you probably have a short to ground(s) somewhere. It is going to be impossible for me to tell you where. But I can give you all of your vehicle's wiring diagrams and tell you how to go about checking individual circuits to track them down. Let me know if that is something that you would like to do. It's not as easy as you think, but it's not as hard as you think either. It will just take a little patience because it's a process of elimination. Get back to us and let us know what you want to do, We are here to help.

Thanks,
Alex
2CarPros

Hello again,

Okay, this might sound overly simple, but believe me, sometimes it really is that easy. So, lets start with checking the connections at the battery terminals. We need to make sure that the connections are corrosion free, tight, and making good metal to metal contact. Double check that all the wires connected to the terminal lugs are insulated and don't have any obvious fraying of the wires.
Please check these for me and get to me with what you find. Please don't assume any of these checks are to trivial. Remember, this is a process of elimination, and wouldn't it be great if this was the problem and we got it right off the bat because we took the time to check instead of assuming something so basic was okay. Let us know and we will go from there.

Thanks,
Alex
2CarPros

Hello again,

Okay, so let's start by explaining how we are going to checking the circuits. You are going to need a multi-meter. We are going to be using it primarily two different ways. 1) Checking for voltage - To do this you are going to put the multi-meter switch in VDC(Volts Direct Current). Select the 20V setting. Your vehicle's electrical system runs on 12 Volts DC, so when we are checking for voltage, put your multi-meter in this setting and usually we are going to be looking for 12-12.6 volts. To simplify this we will call this battery voltage.
2) Voltage Drop - This is the best way to check for resistance and continuity in your vehicle's electrical circuits. To do this testing your vehicle will will have to either be running or have electricity flowing in the circuit. You will have your multi-meter in the same setting as before and you will measure a piece of the circuit. For instance if we wanted to do a voltage drop test on a wire, you would back probe the connector with a safety pin in the cavity where the wire is and do the same on the connector of the other end of the wire. Next you will touch a black probe to one safety pin and the red to the other. Measure the voltage. It should not be more than 0.1 Volts. If there is more than the wire has unwanted resistance and must be replaced. This type of testing will expose any damaged parts of the circuit so they can be replaced.
Okay, I know that that's a lot to take in. So let's make sure again that your battery and the terminal lugs are okay. Let's test the battery voltage to see where the battery stands. Put your multi-meter in #1 setting. Touch the red probe to the positive battery terminal and the black terminal to the negative terminal. Write down what you find. To show you it's okay if you get the probes mixed up and put them backwards, switch the red and black probes so that the black probe is touching the battery positive terminal and the red is touching the battery negative terminal. Write down this reading. Now start your vehicle, and leave it in park. Get out and follow the big wire from your batteries negative terminal to where it connects to the frame. Put one test probe on where it connects to the frame and the other test probe on the where it connects to the battery. Write down the voltage on the multi-meter.
Get back to us with the voltage readings we had you test these techniques with and we will go from there.

Thanks,
Alex
2CarPros

Hello again,

Well it looks like your battery is completely drained dead. I am not sure if it would take a charge if it was put on a charger or not. If your battery is maintenance battery, if it is it will have two little panels on top you can pop off with a screw driver. Each panel has access to three cells. The cells need to be completely immersed in filtered, non tap water. There is a possibility that one cell is in need of water. If they all look good then there is a distinct possibility that you have a shorted, or dead cell. If this is the case the battery is no good and will have to be replaced. Actually if you take the battery down to local Auto Parts store, say like Autozone, they can test it and if good charge it up for you for free. Do this and please get back to us with what you find out. We can go from there, but you will need a fully charged battery before we can continue.

Thanks,
Alex
2CarPros

Hello again,

So every thing that you described was going on when you first asked your question can be a symptom of a bad battery not providing enough voltage to all of those circuits. The two new Direct Trouble Codes(DTC)(s) P0171 and P0420 are also fixable. The first DTC P0171, also, probably is going to be attributed to a weak battery. DTC P0171 is set when your Air:Fuel Ratio is extremely lean, which means you are either getting unmetered air into the air:fuel ratio, or, as is probably what's going on in your case, not enough fuel is making it to the air:fuel ratio. This is probably being caused, again, by the extremely weak battery not providing enough voltage to the fuel pump.
The second DTC P0420 is not going to be attributed to the extremely weak battery. This DTC is for the Bank 1 catalytic converter is below useful operating threshold. Basically, the Bank 1 Catalytic Converter is worn out and your vehicle needs a new one. This happens through normal wear and tear and is expected to happen in your vehicle's lifetime. Depending on where you live a catalytic converter will run you from around $75.00 anywhere but California to around $125.00 if you live in California. The difference in price is due to California having more stringent regulations than the rest of the country. If you want to replace the Catalytic Converter yourself let us know and we can provide you with step by instructions on how to do this.
Having said all that, I think with a new battery and catalytic converter your vehicle will be fixed and ready to go. Let us know what you decide to do.

Thanks,
Alex
2CarPros

Hello again,

No. The Malfunction Indicator Lamp (MIL) AKA, "check engine" light will always be on. You can erase the DTC out of the Keep Alive Memory (KAM), but it will just come back on every time you do a drive cycle.

Thanks,
Alex
2CarPros

Hello again,

Okay what is going on with the radio and headlights. You should unplug the negative battery terminal while we figure this out incase you have a short to power somewhere. I would hate to see your new battery get drained dead.

Thanks,
Alex
2CarPros