P2191: System Too Lean at Higher Load (Bank 1)

What does P2191 mean?

P2191 sets once bank 1's long-term trim has run into its enrichment limit in the upper load range, so the engine would be lean there without the correction. It is the third load zone next to P2187 (idle) and P2177 (off idle), and it is where a supply that copes at cruise first falls short: a tired fuel pump, a clogged filter, poor pressure regulation, injectors that flow too little, or an air mass sensor that reads low at high airflow. CARB demands a fault once adaptive control has used up the adjustment the maker allows (13 CCR 1968.2 (e)(6.2.2)). No manufacturer publishes its criteria for P2191; GM covers the load range with P2177 and a factor of 1.23 instead, and Kia lists only the rich sibling P2192 for the Rio and Soul 1.6 GDI. Drivers may feel hesitation when accelerating hard.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Hesitation or flat spot under heavy throttle
• Loss of power when climbing or towing
• High positive long-term fuel trim at high load only

Common causes

• High Fuel pump or pressure regulation unable to hold pressure at high demand
• Medium Clogged fuel filter or strainer
• Medium Air mass sensor under-reading at high airflow
• Medium Partly blocked injectors on bank 1
• Low Charge-air or intake leak behind the air mass sensor (turbo engines)

Likelihood is a general estimate across vehicles; your make and model may differ.