P219A-85: Bank 1 Air-Fuel Ratio Imbalance - Signal above allowable range: Action

NOTE: Operational requirements needed to allow the monitor to be fully tested. Engine coolant temperature greater than 50°C, drive vehicle at steady load in 6th gear to achieve an engine speed of 1200-2400rpm, maintain these conditions for 10 minutes (highway cruise)

Using the manufacturer approved diagnostic system check engine control module for related misfire DTCs and refer to this DTC index. Rectify these first
Inspect connectors for signs of water ingress, and pins for damage and/or corrosion
Check for air leak on intake manifold to cylinder head connection
Check for external fuel leak at fuel injector
Check for fuel restriction within fuel injector
Check for damage/restriction of fuel rail
Check for air leak around spark plug
Check for air leak around fuel injector
Check and install a new fuel injector as required
Check and install a new ignition coil as required
Using the manufacturer approved diagnostic system clear all stored DTCs using the `Diagnosis Menu' tab and retest