Fuel and air

P2190 — System Too Rich at Idle (Bank 1)

Severity: medium Drive with care, to a shop

What P2190 means

The engine control module uses the oxygen sensor signal and fuel trims to judge the mixture at idle on bank 1. Normally it adjusts injector pulse width to keep the mixture near stoichiometric, cutting fuel when the sensor reads rich. P2190 is set when the correction reaches its limit and the mixture is still too rich.

Symptoms

  • Rough idle
  • Fuel smell from the cabin or exhaust
  • Check Engine light on
  • Possible misfire or hesitation
  • Increased fuel consumption
  • Black smoke or soot at the tailpipe
  • Often accompanied by P0172

Possible causes

  1. Leaking fuel injector at idle
  2. EVAP purge valve stuck open
  3. Dirty MAF sensor reading low airflow
  4. High fuel pressure or a faulty pressure regulator
  5. Clogged air filter or restricted intake
  6. Faulty bank 1 oxygen sensor or its circuit
  7. Wiring short to ground or to positive in sensor or injector circuits
  8. Rarely, a faulty ECM

How to diagnose

  1. Scan for codes and freeze-frame data, noting P0172 or other codes
  2. View short- and long-term fuel trims at idle and at about 2,500 rpm
  3. Inspect the air filter and intake tract for restrictions
  4. Compare MAF readings with expected values and clean the sensor if needed
  5. Test the purge valve: it should stay closed unpowered and hold vacuum
  6. Measure fuel pressure and check for pressure drop after shutoff
  7. Test injectors for resistance, cylinder balance and leakage
  8. Inspect wiring and connectors of the oxygen sensor and injectors for shorts, and check the sensor signal

Common fixes

  • Clean or replace the MAF sensor
  • Replace the purge valve
  • Replace a leaking injector or the whole set
  • Replace the fuel pressure regulator or fuel pump if readings are off
  • Replace the air filter and clear any intake restriction
  • Repair damaged wiring or replace the oxygen sensor

Questions and answers

What does P2190 mean?

It means the mixture on bank 1 is too rich at idle. The engine computer can't cut fuel enough to bring it back to normal.

Can I drive with P2190?

Short trips are usually possible, but get it repaired soon. A rich mixture can damage the catalytic converter and raise fuel use.

What should I check first?

Start with fuel trims, the air filter, the MAF sensor and the purge valve. Then check fuel pressure and the injectors.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.