Car is a 2002 6 speed coupe with 49k miles.

So after about 45 minutes of driving, (was getting on it a bit, but nothing crazy), my engine light came on. I took it to the local autozone and had them scan my car, and code P0131 came up. Now this code is showing as the Bank 1 Sensor 1 O2 sensor having low voltage, but the guy tried telling me that the car needs a new intake manifold gasket? Can anyone help me out?

 

Hi !!...sorry to hear about your car issues....the guy at The Zone could have been partly on the right track or maybe even right...3 things can cause this DTC to set...bad O2 sensor, bad O2 sensor wiring or even yet a vacuum leak or bad injector, leaky intake runner on the left bank, or an exhaust leak just upstream of the O2 sensor...you would really need a scan tool to nail this down diagnosis down...to explain what's happening here is the left O2 sensor is seeing a lean condition which is causing the O2 millivoltage to drop below 200 mv...anything under 450 mv is lean...when the engine computer sees this condition for around 30 seconds the DTC will set...to verify that it is indeed a lean condition you would have to look at your fuel trims on a scan tool...they will be positive....NOW... if it is a bad O2 sensor or wiring causing the "FALSE" lean condition and you have NO vacuum leak the extra fuel that the PCM is adding will make the car run very RICH...your exhaust will be very SMELLY...now to rule out wiring you have to get under the car and unplug the O2 sensor connector and take some voltage reading...I don't know of your mechanical abilities...so in a nutshell without a scan tool to diagnose this will be pretty difficult...having a scan tool will allow you to look at "freeze frame" data and tell you what the computer was seeing when the DTC set..things like your RPM, the engine load, the fuel trims etc !!

 

Couple of quick and easy things to check if you have a way to lift the car safely (ramps, etc.). Check the O2 wiring for any burnt wires, bad plugs, etc. Then run the motor and spray some WD-40 or throttle body clean near the gaskets where the intake meets the head. Any leaks should show up with an idle change because a leak should take in some of the fluid and cause it to change idle. Prior to doing this, vacuum the area so you don't send in any dirt. It also wouldn't hurt to clean the MAF, but this will usually cause an issue on both banks.

 

 

I got a similar code after removing my H pipe and reinstalling. I knew the donut gasket wasn't sealing so took it off again and used copper RTV. Hasn't came back in over a year