P0169
Incorrect Fuel Composition
- Severity
- Medium
- Driving
- Short journeys only
The fuel in the tank is not what the module expects. On a flexible fuel vehicle the module measures how much ethanol the fuel contains and adjusts fuelling and timing to suit, because ethanol needs a richer mixture than petrol. This code means that measurement is outside the range the vehicle can adapt to - either the fuel really is wrong, or the sensor measuring it is.
Possible causes
- CommonFuel filled that the vehicle is not designed to run on
- CommonFuel composition sensor fault or drift
- CommonSensor not yet relearned after a fuel change - the module needs a few miles to adapt
- PossibleWater or other contamination in the fuel
- PossibleWiring or connector fault at the composition sensor
What you might notice
- Rough running, hesitation or misfire
- Hard starting, especially in cold weather
- Loss of power
- Poor fuel economy
- Check engine light on
What to check, in order
- Establish what was last put in the tank, and where. This code very often follows a fill at an unfamiliar pump, and the answer is in the receipt rather than in the wiring.
- Read the ethanol percentage on live data and compare it against what should have been filled. A vehicle running on ordinary petrol should read close to the local blend.
- Drive a few miles after a fuel change before condemning anything. The module needs distance to relearn, and the code can appear simply because it has not finished.
- If genuinely wrong fuel has been added, have the tank drained rather than diluting it. Running an engine on fuel it was not built for causes damage that costs far more than a drain.
- Check for water contamination. Water gives readings that look like an ethanol fault and damages the injection system in its own right.
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
P0100P0101P0102P0103P0104P0105P0106P0107P0108P0109P0110P0111P0112P0113P0114P0115P0116P0117P0118P0119P0120P0121P0122P0123P0124P0125P0126P0127P0128P0129P0130P0131P0132P0133P0134P0135P0136P0137P0138P0139P0140P0141P0142P0143P0144P0145P0146P0147P0148P0149P0150P0151P0152P0153P0154P0155P0156P0157P0158P0159P0160P0161P0162P0163P0164P0165P0166P0167P0168P0169P0170P0171P0172P0173P0174P0175P0176P0177P0178P0179P0180P0181P0182P0183P0184P0185P0186P0187P0188P0189P0190P0191P0192P0193P0194P0195P0196P0197P0198P0199