Can I drive with the transmission temperature light on?

No, and the reason is that the car will let you. Unlike an engine seizing, an overheating gearbox keeps working right up until it does not, so nothing forces you to stop. Meanwhile the fluid is oxidising and losing its ability to lubricate, and that damage is permanent. Pull over, let it cool properly, and if the lamp comes back shortly after setting off again, get it recovered.

What causes an automatic gearbox to overheat?

Load and poor cooling, in some combination. Towing, heavy loads and long climbs put sustained work through the transmission; hot weather and crawling traffic remove the airflow that would normally carry the heat away. On top of that, low or old fluid carries heat far less effectively, a blocked cooler or a radiator matrix full of debris stops it being shed at all, and a slipping torque converter lock-up clutch generates heat continuously even at a steady cruise.

Should I switch the engine off if the gearbox is overheating?

Check the handbook, because the usual advice runs against instinct. On many automatics the recommendation is to stop the car, select Park or Neutral and leave the engine idling for a few minutes, since that keeps fluid pumping through the cooler and brings the temperature down much faster. Switching off stops the flow and lets the heat soak into the surrounding metal. Either way, do not carry on driving, and allow half an hour or more before deciding to continue.

Does towing damage an automatic gearbox?

Towing within the car's rated limits does not damage a healthy gearbox, but it is the single hardest thing most automatics are asked to do, and heat is the mechanism by which it goes wrong. A car towing near its limit up a long gradient in summer can push fluid temperature past the safe threshold within minutes. If you tow regularly, an auxiliary transmission cooler and shorter fluid change intervals than the handbook's headline figure are both worth having, and manufacturers frequently specify exactly that for towing use.

Dashboard warning light

Transmission temperature warning light

Last updated 27 July 2026

Quick answer

The automatic transmission fluid is hotter than it is designed to run. Heat is what kills automatic gearboxes, and the damage is cumulative and permanent, so this is a stop-and-cool warning rather than a get-it-looked-at-soon one.

What to do: Stop as soon as it is safe
Can you drive?: No

Why it is red

Reserved for hazards and for faults where continuing could injure somebody or destroy something expensive. Most red lamps mean stop, though a few mean the opposite, so read the lamp rather than the colour.

What turns it on

A sensor in the transmission sump or valve body reports fluid temperature to the control unit, which lights the lamp when it passes a set threshold — typically somewhere around 120 to 130 degrees Celsius depending on the make. Above roughly that point the fluid oxidises rapidly, loses its ability to lubricate and transfer torque, and starts varnishing the internals.

What to do about it

Stop as soon as it is safe. Continuing is the whole problem: every additional mile at temperature ages the fluid further and the harm does not reverse when it cools.
Check the handbook before switching off. Many manufacturers advise leaving the engine idling in Park or Neutral for a few minutes, because that keeps fluid circulating through the cooler and drops the temperature far faster than switching off, which stops the flow and lets heat soak.
If you are towing, uncouple if you sensibly can, or at least stop climbing. Towing up a long gradient in high summer is the classic way to see this lamp.
Allow a proper cooling period, meaning half an hour or more rather than a few minutes, before deciding whether to continue.
Look underneath for a leak and at the front of the car for a blocked transmission cooler or radiator matrix, which are two of the commonest fixable causes.
Have the fluid inspected once you get to a garage. Fluid that has been cooked smells burnt and turns dark brown, and at that point changing it is a repair rather than maintenance.

Can you keep driving?

Not while it is lit. The gearbox will usually still drive, which is exactly what makes this warning easy to ignore and expensive to ignore. Overheated fluid does not recover, and a gearbox run hot enough for long enough needs a rebuild rather than a service. Stop, let it cool properly, and if the lamp returns within a few miles of setting off again, have the car recovered rather than nursing it home.

What causes it

Towing or carrying a heavy load, particularly on long climbs or in hot weather
Prolonged stop-start traffic in high temperatures, where there is no airflow over the cooler
Low transmission fluid, so there is less of it to absorb and carry away heat
Old, degraded fluid that no longer transfers heat or lubricates as it should
A blocked or damaged transmission oil cooler, or a radiator matrix packed with leaves and flies
A torque converter lock-up clutch that is slipping instead of locking, which generates heat continuously at a steady cruise
Internal clutch pack slip from wear, which both causes and is worsened by the heat
A failing temperature sensor reporting a temperature the gearbox is not actually at

Does it fail an MOT?

Not on its own — but what causes it often does.

There is no MOT check on transmission temperature, fluid or condition, and no defect for this lamp. The indirect route is the same as for any other gearbox problem: since 2018 a fluid leak that could harm the environment or another road user is a defect, and a low fluid level is both a common cause of overheating and something a tester may see as a drip or a wet gearbox casing from underneath.

Fault codes that turn this light on

The lamp tells you which system reported a problem. The code stored behind it names the check that failed, which is the difference between knowing something is wrong and knowing where to look. These are the ones that commonly sit behind this symbol.

P0218Transmission Fluid Over Temperature
P0711Transmission Fluid Temperature Sensor A Circuit Range or Performance
P0712Transmission Fluid Temperature Sensor Circuit Low
P0713Transmission Fluid Temperature Sensor Circuit High

Got a different code? Look it up — the index covers every standard OBD-II code.

Common questions

Can I drive with the transmission temperature light on?: No, and the reason is that the car will let you. Unlike an engine seizing, an overheating gearbox keeps working right up until it does not, so nothing forces you to stop. Meanwhile the fluid is oxidising and losing its ability to lubricate, and that damage is permanent. Pull over, let it cool properly, and if the lamp comes back shortly after setting off again, get it recovered.
What causes an automatic gearbox to overheat?: Load and poor cooling, in some combination. Towing, heavy loads and long climbs put sustained work through the transmission; hot weather and crawling traffic remove the airflow that would normally carry the heat away. On top of that, low or old fluid carries heat far less effectively, a blocked cooler or a radiator matrix full of debris stops it being shed at all, and a slipping torque converter lock-up clutch generates heat continuously even at a steady cruise.
Should I switch the engine off if the gearbox is overheating?: Check the handbook, because the usual advice runs against instinct. On many automatics the recommendation is to stop the car, select Park or Neutral and leave the engine idling for a few minutes, since that keeps fluid pumping through the cooler and brings the temperature down much faster. Switching off stops the flow and lets the heat soak into the surrounding metal. Either way, do not carry on driving, and allow half an hour or more before deciding to continue.
Does towing damage an automatic gearbox?: Towing within the car's rated limits does not damage a healthy gearbox, but it is the single hardest thing most automatics are asked to do, and heat is the mechanism by which it goes wrong. A car towing near its limit up a long gradient in summer can push fluid temperature past the safe threshold within minutes. If you tow regularly, an auxiliary transmission cooler and shorter fluid change intervals than the handbook's headline figure are both worth having, and manufacturers frequently specify exactly that for towing use.

This is general guidance, not a diagnosis. Manufacturers draw the same system differently and reuse symbols for more than one function, so check the handbook for your own car before acting on anything here.

Check what your car has actually failed on

Free MOT history for any UK registration, straight from DVSA records.