Pair of OBD-II codes today

I picked up a CEL on my way home on a two-hour Interstate drive this afternoon:

P0174: [FONT=arial,verdana,helvetica,sans-serif][SIZE=-0][FONT=arial,verdana,helvetica,sans-serif]System Too Lean - Bank No. 2.[/FONT][/SIZE][/FONT]
P1151: Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2.

So... what am I looking at? bad sensor? (Which sensor is it? How much?) clogged cats? Run some Seafoam?

Thanks,
Bob

How many miles on the Bank 2 (radiator side) Upper O2 sensor? If more than 75k miles, change that first. Check for vacuum leaks in the vacuum hoses.

This Bank 2 Upper O2 sensor is the one to the left of the exhaust manifold when you are standing in front of the radiator. Remove the oil filter for more room to manuevre the tool for removing the O2 sensor. 7/8 inch, 22mm or O2 sensor removal tool from Autozone or Advance.

I'm guessing ~96, like the rest of the car. I've only had it for about 8k.

How do I check vacuum leaks?

If it is a big leak, you should hear a hissing sound. If it is a "small imperceptible to the ear" leak, then you need to spray some carb cleaner at suspect areas, like hose clamps, UIM/LIM gasket areas, etc. Basically, you are trying to catch a change in the engine speed (faster or slower)when the carb cleaner enters the engine.

Okay, I have the sensor and the special socket... it's the one right next to my oil filter, right?

bobbo said:

Okay, I have the sensor and the special socket... it's the one right next to my oil filter, right?

Click to expand...

Yes..