P0171 code too lean bank1 2013 Mazda 5 minivan

Question

What causes this code specifically? Changed air filter with Mann replacement 2months ago. Saw code after on incline on gravel driveway not sure if that is coincidence or not.

Answer 1

P0171 Fuel trim lean Bank 1

When air filter  replacement  you should do a MAF air cleaning, with a suitable MAF cleaning,

 When you do a airfilter change , what is also recommended is to do a MAF cleaning. This also helps in perfromance of the MAF Using a suitable MAF cleaning product

 Todays airfilter regardless is it is OEM or aftermarket, all manufactuer of air filter has to apply a fire retardant on the airfilter, this limits liabilty in case the engine had a back fire and the airfilter caught on fire. They also have to comply with this in order to transport the product to market for sale. The problem about this is the fire retardant tends to mask the MAF ability to operate correctly, setting a fuel trim lean code condition.  using a MAF cleaning prior to the airfilter replacement is recommended.