Have you had any recent work done to the vehicle were the Battery was Disconnected? The P1684 indicates that the battery has been disconnected withing the last 50 starts.
Now the P0171 - Lean Condition Bank 1 - that plus the engines high Idle could be a vacuum leak. If you are attempting to fix yourself, take a look at all the vacuum lines around the engine. Look for broke, cracked, soft, and cracked hoses. Also make sure the air intake duct from the air filter housing to the throttle body is in good condition and that the clamps are tight.
For more on lean condition causes check link below...
Saturday, November 21st, 2009 AT 7:16 PM