P2186
Engine Coolant Temperature Sensor 2 Circuit Intermittent/Erratic
- Severity
- Medium
- Driving
- Drivable — book it in
The coolant temperature sensor 2 signal is dropping out or jumping. Connections are more likely than the sensor.
Possible causes
- CommonFailed coolant temperature sensor
- CommonCorroded connector or damaged wiring
- CommonLow coolant level, leaving the sensor uncovered
- CommonAir lock in the cooling system after a previous repair
- PossibleLoss of reference voltage or earth
- PossibleThermostat fault, so the temperature genuinely is wrong
What you might notice
- Temperature gauge wrong or erratic
- Cooling fans running constantly or not at all
- Poor fuel economy
- Hard starting
- Heater blowing cool
- Check engine light on
What to check, in order
- Compare the reported temperature with the other coolant sensor and with ambient on a vehicle that has stood overnight. All should agree closely when cold.
- Check the coolant level and look for leaks. A low level uncovers the sensor and produces these codes with a good sensor.
- Inspect the connector for corrosion.
- Check the reference voltage and earth at the sensor.
- Watch the temperature climb from cold on a drive - it should rise smoothly and settle.
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