Got these codes on the 975 miles drive home after buying my new 2000 Disco. Got them about half way in, stopped at an O'reilly's and found out that the codes mean...

PO154: O2 sensor circuit, no activity decteted. Bank 2 Sensor 1
PO174: System too lean. Bank 2.

Any help would be greatly appreciated on what exactly caused these to go off, and what I need to do to fix.

Thanks guys...oh and the disco has 78,000 miles.

Sidenote: Tonight spend 5 hours on base at the auto shop doing both diffs, oil change, transfer case oil change, tranny fluid and filter change, and installing my new front driveshaft (with spicer u-joints!!).

 

You need to replace your passenger side O2 sensors. At your mileage you may think about replacing them all. They are on sale for $60 each at Atlantic British.