P2190: System Too Rich at Idle (Bank 2)

What does P2190 mean?

P2190 is the bank 2 counterpart of P2188: the long-term trim of bank 2 has to remove more fuel than allowed at idle and low load. GM's 2008 3.6 LLT sets it below -6.0 % in the same window it uses for P2188 (520 to 1120 rpm, 1.7 to 7.8 g/s, closed loop, coolant above 60 °C, catalyst heating not active), and GM's 2005 2.8 and 3.6 V6 treat it in the same additive adaptation range. A rich fault on bank 2 only usually lies in that bank: a leaking injector, or a bank 2 front sensor reading lean so the ECM keeps leaning the mixture. Fuel pressure, purge vapour and air-mass errors act on both banks and tend to set P2188 and P2190 together. Stellantis is an example: an airflow straightener clipped in wrong in the air box upset the air mass reading and logged P2188 and P2190 together, sometimes with P0111 and an unstable idle; refitting it correctly cured it.

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

Symptoms

• Malfunction indicator lamp on
• Rough idle, fuel smell

Common causes

• Medium Leaking injector on bank 2
• Medium Shared cause such as air mass error or purge vapour, usually with P2188 too
• Low Bank 2 front sensor reading lean

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