I installed a new battery and the engine is now throwing - P0171 -> P0101 -> P0138.

I installed a new battery and the engine is now throwing - P0171 -> P0101 -> P0138. Prior to the battery install I had never had a CEL come on since I've owned it. It's a 2008 with 180k miles on it.

I don't notice much other than little shake/knock at low RPM after starting up. Once it's warmed up, it seems to go away.

This is based off the scan from AutoZone

1. P0171 -System too Lean (A/F Lean, Bank 1)

Secondary DTCs

1. P0101 - Mass or Volume Air Flow Circuit Range/Performance
2. P0138 - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2

I replaced my MAF with a Denso (bought of Amazon and assume it's real).


Any advice on what my next steps should be? Based off what I've read it could be a whole slew of things - O2 sensor, fuel injectors, manifold leak, or other vacuum leaks.

 

Clear the codes and see if they come back. Battery replacement can cause some wonky stuff when you reconnect it. If you didn't have issues prior to replacing the battery, then clear the codes and see what comes back, if anything, before you try doing any fixes.

 

Look around the battery, are there any hoses that you moved aside or yanked on to get the battery installed? Look for broken plastic connection and cracks near hose ends.