P2188
System Too Rich at Idle (Bank 1)
- Severity
- Medium
- Driving
- Drivable — book it in
The mixture on bank 1 is too rich - too much fuel for the air available - and specifically when running at idle, with the throttle closed. The module has run out of adjustment trying to correct it. The condition named in the code is the useful part: At idle the engine draws very little air, so any leak makes a large proportional difference - which is why a vacuum leak shows here before it shows anywhere else.
Possible causes
- CommonLeaking or stuck-open fuel injector
- CommonFuel pressure regulator letting pressure run high
- CommonMass airflow sensor over-reporting airflow
- CommonRestricted air filter starving the engine of air
- PossibleFaulty coolant temperature sensor making the module think the engine is cold
- PossibleFailing oxygen sensor reporting rich incorrectly
What you might notice
- Black smoke from the exhaust
- Strong fuel smell
- Poor fuel economy
- Rough idle
- Spark plugs fouled with soot
What to check, in order
- Check the air filter. A heavily restricted filter is the cheapest possible cause and worth eliminating first.
- Watch fuel trim on the live data screen - strongly negative trim confirms the module is cutting fuel to compensate.
- Check the coolant temperature sensor reads plausibly. A sensor stuck reading cold makes the module enrich the mixture permanently.
- Test fuel pressure against specification.
- Inspect the spark plugs - uniform soot across all of them supports a whole-bank rich condition rather than one bad injector.
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 and air metering
P2100P2101P2102P2103P2104P2105P2106P2107P2108P2109P2110P2111P2112P2113P2114P2115P2116P2117P2118P2119P2120P2121P2122P2123P2124P2125P2126P2127P2128P2129P2130P2131P2132P2133P2134P2135P2136P2137P2138P2139P2140P2141P2142P2143P2144P2145P2146P2147P2148P2149P2150P2151P2152P2153P2154P2155P2156P2157P2158P2159P2160P2161P2162P2163P2164P2165P2166P2167P2168P2169P2170P2171P2172P2173P2174P2175P2176P2177P2178P2179P2180P2181P2182P2183P2184P2185P2186P2187P2188P2189P2190P2191P2192P2193P2194P2195P2196P2197P2198P2199