How much does it cost to fix P2099?

DIY repair typically costs $20–$200 for parts. Professional repair runs $150–$800 including parts and labor.

P2099

Powertrain

Moderate

Post Catalyst Fuel Trim System Too Rich (Bank 2)

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The P2099 code is the bank 2 version of P2097, indicating that the post-catalyst fuel trim system on bank 2 is running too rich. The PCM has determined that the exhaust mixture downstream of the bank 2 catalytic converter contains too much fuel relative to air. This code only appears on vehicles with V-type or boxer engines that have separate exhaust banks.

The diagnostic approach mirrors P2097 but targets the bank 2 side specifically. Check for leaking injectors, test fuel pressure, and inspect the downstream O2 sensor on bank 2. If you see P2099 along with P2097 (both banks rich), the issue is likely system-wide — such as excessive fuel pressure or a saturated EVAP canister — rather than specific to one bank.

Don't delay in addressing this code. Running rich wastes fuel, contaminates the catalytic converter with unburned fuel, and can shorten converter life significantly. A fuel-smell from the exhaust is a strong indicator of a real rich condition that needs immediate attention.

Severity

Moderate — Address SoonThis Week

Symptoms

•Check engine light on
•Fuel odor from the exhaust
•Poor fuel economy
•Black or dark exhaust smoke in severe cases
•Rough idle or stumbling

Likely Causes

Leaking fuel injector on bank 230%

A fuel injector on the bank 2 side that doesn't seal properly or is stuck partially open delivers excess fuel, creating a rich exhaust condition detected by the downstream oxygen sensor.

Failing bank 2 downstream oxygen sensor25%

A degraded post-catalyst O2 sensor on bank 2 may provide consistently rich-biased readings, causing the PCM to flag a rich fuel trim condition even if the actual mixture is normal.

High fuel pressure from faulty regulator25%

Since fuel pressure affects all injectors, a faulty regulator can cause a rich condition on both banks — but if bank 2 is more sensitive or has other minor issues, P2099 may appear first or alone.

EVAP system purge issue enriching bank 220%

Excessive fuel vapor purge from the EVAP canister into the intake manifold can disproportionately affect bank 2 cylinders depending on the purge valve location and intake manifold design.