Exhaust Gas Temperature Too High (Bank 1)

Possible causes

• CommonDiesel particulate filter regeneration running longer or hotter than intended, often because previous regenerations were interrupted by short journeys
• CommonEngine running rich, so fuel is still burning in the exhaust
• CommonMisfire sending unburnt fuel into the exhaust to ignite there
• CommonIgnition timing retarded, whether commanded or from a timing fault
• CommonFailed exhaust gas temperature sensor reading high
• PossibleBlocked particulate filter or a partly melted catalytic converter restricting flow
• PossibleTurbocharger or boost control fault causing overfuelling

What you might notice

• Loss of power, or the car dropping into limp mode
• Smell of burning, or a glowing exhaust component in the dark
• Warning light for the particulate filter on a diesel
• Rattling or loss of power that worsens - a sign the converter is breaking up
• Check engine light on

What to check, in order

1. Read all codes first. A misfire or a fuelling fault stored alongside is what is heating the exhaust, and it is the fault to fix - this code is the consequence.
2. On a diesel, check whether the particulate filter is trying to regenerate and cannot finish. A cycle of short journeys leaves it loaded and every attempt at regeneration runs hotter than the last.
3. Compare the temperature reading against the other exhaust sensors. One sensor far out of step with the rest is the sensor; all of them high together is real.
4. Look for a restriction. A blocked filter or a collapsed converter raises temperature and back pressure together, and back pressure is straightforward to measure.
5. Do not simply clear this and carry on. The reading is usually true, and what it is describing destroys expensive components quickly.