Powertrain, generic (extended)

P2191 System Too Lean at Higher Load (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

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

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

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–900
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel pumpfuel filterfuel injectormass air flow sensor

Related codes

P2193P2192P2177P2187P0171

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.