P2190 – System Too Rich at Idle Bank 2

P2190 – System Too Rich at Idle (Bank 2) means the ECM/PCM has detected that the air-fuel mixture on Bank 2 is richer than expected **specifically during idle conditions**. A rich mixture means too much fuel or not enough air entering the combustion chamber. This often causes rough idle, increased fuel consumption, black smoke, and strong fuel odors. If ignored, it can damage the catalytic converter on Bank 2. This guide explains what P2190 means, symptoms, causes, diagnostics, and the most effective fixes.

What Does P2190 Mean?

P2190 is a generic OBD-II code indicating that the ECM has reached the limit of how much fuel it can subtract from Bank 2 during idle. Fuel trims go heavily negative when the ECM is correcting a rich condition. When these corrections exceed a programmed threshold, the code is set.

Because Bank 2 is affected, the issue is usually limited to the cylinders on that side of the engine. Common causes include leaking injectors, PCV faults, purge-system issues, stuck O2 sensors, and incorrect airflow readings from a dirty MAF sensor.

Quick Reference

• OBD-II Family: P-Code (Powertrain)
• Scope: Generic
• System: Fuel & Air Metering
• Difficulty Level: Moderate
• Estimated Repair Cost: €40–€350
• Last Updated: 28 November 2025

Real-World Example / Field Notes

A V6 engine arrived with rough idle and strong exhaust fumes. Fuel trims showed Bank 2 at –28% while Bank 1 was normal. A leaking injector on cylinder 4 was dribbling fuel at idle. Replacing the injector and performing a fuel trim relearn corrected the rich condition and cleared P2190.

Another example involved a turbocharged engine where the PCV valve was stuck open, pulling oil vapor into Bank 2’s intake runners at idle. Cleaning the intake, replacing the PCV valve, and clearing the trims resolved the code permanently.

Symptoms of P2190 – System Too Rich at Idle (Bank 2)

• Rough idle: Shaking or unstable engine at standstill.
• Fuel smell: Excess fuel or vapor near the exhaust.
• Black smoke: Rich combustion on Bank 2 cylinders.
• Poor fuel economy: Significant increase in consumption.
• Warm starting issues: Cylinders may flood with excess fuel.
• Check engine light: Often accompanied by O2 or MAF codes.

Common Causes of P2190

Most Common Causes

• Leaking or stuck-open injector on Bank 2
• Faulty front O2 (A/F) sensor on Bank 2 giving rich signals
• PCV valve stuck open, adding unwanted vapor at idle
• Dirty or faulty MAF sensor causing incorrect airflow data
• Fuel pressure too high due to regulator or return-system failure

Less Common Causes

• Purge valve stuck open, allowing fuel vapors into intake
• Exhaust leaks near Bank 2 upstream O2 sensor
• Faulty coolant temp sensor causing enriched idle mixture
• Incorrect fuel pressure after recent repair
• PCM/ECM fault (rare)

Diagnosis: Step-by-Step Guide

P2190 diagnosis focuses on sensors, fuel trim behavior, injector leakage, and idle airflow control on Bank 2.

Tools You’ll Need

OBD-II scanner with fuel-trim data, multimeter, fuel-pressure gauge, injector balance tester, smoke machine, and basic hand tools.

1. Check fuel trims: Confirm heavy negative trims only on Bank 2 at idle.
2. Inspect the intake system: Ensure no blockages or contamination.
3. Check MAF sensor: Clean if oily or contaminated; verify airflow readings.
4. Inspect PCV valve: Verify it seals correctly and isn’t pulling excess air/fuel vapors.
5. Test purge valve: Ensure it isn’t leaking vapors into intake at idle.
6. Perform injector balance test on Bank 2: Identify stuck or leaking injectors.
7. Measure fuel pressure: High pressure strongly contributes to rich idle conditions.
8. Test front O2/A/F sensor: Look for stuck-rich or slow-responding signals.
9. Smoke test intake: Ensure no leaks are altering idle airflow.
10. Verify coolant temperature sensor readings: Incorrect cold readings command extra fuel.

Pro Tip: If Bank 1 trims are normal but Bank 2 is rich, suspect injectors or O2 sensors specifically on Bank 2 — not global sensors like the MAF.

Possible Fixes & Repair Costs

• Replace leaking injector(s): €60–€180 each
• Replace or clean MAF sensor: €20–€120
• Replace PCV valve: €10–€40
• Repair or replace purge valve: €40–€120
• Replace front O2/A/F sensor: €60–€180
• Fix fuel pressure regulator: €50–€150

Can I Still Drive With P2190?

Driving with P2190 is not recommended. A rich mixture on Bank 2 can foul spark plugs, cause misfires, wash down cylinder walls, and damage the catalytic converter. If the engine runs rough at idle, avoid driving until repairs are completed.

Related Too Rich Codes

Compare nearby too rich trouble codes with similar definitions, fault patterns, and diagnostic paths.

• P2180 – System Too Rich Off Idle Bank 2
• P2178 – System Too Rich Off Idle Bank 1
• P2188 – System Too Rich at Idle Bank 1
• P2194 – System Too Rich at Higher Load Bank 2
• P2192 – System Too Rich at Higher Load Bank 1
• P2189 – System Too Lean at Idle Bank 2

Key Takeaways

• P2190 indicates Bank 2 is running excessively rich during idle.
• Common causes include injector leakage, PCV faults, purge faults, and sensor errors.
• Ignoring the code risks catalytic-converter damage on Bank 2.
• Fuel trims and injector testing are essential for accurate diagnosis.

FAQ

What makes P2190 specific to Bank 2?

Only the cylinders on Bank 2 show excessive fuel enrichment, indicating the issue is not global but isolated to one side of the engine.

Can a bad MAF sensor trigger P2190?

Yes. Incorrect airflow readings can confuse idle fueling, even if only one bank shows the error.

Does P2190 damage the catalytic converter?

Yes, a rich mixture overheats and degrades the catalyst over time.

Will injector cleaner fix a leaking injector?

Unlikely. A physically leaking injector usually requires replacement.

Can P2190 be caused by a purge valve stuck open?

Yes. Extra fuel vapor entering at idle creates a rich condition on the affected bank.