P2097
Post Catalyst Fuel Trim System Too Rich (Bank 1)
- Severity
- Medium
- Driving
- Drivable — book it in
The mixture measured after the catalytic converter on bank 1 is too rich - too much fuel for the air available - and the module has run out of adjustment trying to correct it. A genuinely rich mixture wastes fuel, fouls plugs and shortens the converter's life, so it is worth finding even though the car may drive normally.
Possible causes
- CommonLeaking or dirty fuel injector
- CommonFailing downstream oxygen sensor
- CommonFuel pressure regulator letting pressure run high
- PossibleMass airflow sensor over-reporting airflow
- PossibleFailing catalytic converter
- PossibleCoolant temperature sensor making the module think the engine is cold
What you might notice
- Check engine light on
- Failed emissions test
- Poor fuel economy
- Smell of fuel from the exhaust
- Black smoke in some cases
What to check, in order
- Read all codes. Upstream fuel trim codes alongside this one mean the mixture is genuinely rich and the cause is upstream of the converter.
- Watch fuel trim on the live data screen - strongly negative trim confirms the module is cutting fuel to compensate.
- Check fuel pressure against specification.
- Check the coolant temperature sensor reads plausibly. A sensor stuck reading cold makes the module enrich the mixture permanently.
- Do not replace the catalytic converter on this code alone - and note that a converter damaged by a long-running rich mixture is a symptom, not the cause.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Fuel, air metering and auxiliary emission controls
P2000P2001P2002P2003P2004P2005P2006P2007P2008P2009P2010P2011P2012P2013P2014P2015P2016P2017P2018P2019P2020P2021P2022P2023P2024P2025P2026P2027P2028P2029P2030P2031P2032P2033P2034P2035P2036P2037P2038P2039P2040P2041P2042P2043P2044P2045P2046P2047P2048P2049P2050P2051P2052P2053P2054P2055P2056P2057P2058P2059P2060P2061P2062P2063P2064P2065P2066P2067P2068P2069P2070P2071P2075P2076P2077P2078P2079P2080P2081P2082P2083P2084P2085P2086P2087P2088P2089P2090P2091P2092P2093P2094P2095P2096P2097P2098P2099