When things light up on your dashboard, you may have an issue. Though the lights and symbols are apparent most of the time, one of them is “AT Oil Temp,” leaving many car owners scratching their heads.
The text might seem specific, but there are a few reasons why the AT oil temp symbol can light up, a few of which we’ll explain below.
A steady, solid AT Oil Temp light means your transmission fluid has overheated. This usually happens after towing a heavy load, driving at high speeds for several hours, or climbing steep hills repeatedly. The fix is simple, but you need to act quickly.
Pull over as soon as it’s safe to do so, but don’t turn the engine off. Leave it idling instead. An idling engine keeps coolant circulating, which helps the transmission cool down faster than shutting everything off. Wait until the light goes out on its own before getting back on the road.
If the light comes back after cooling down, that’s a sign of a deeper problem, like low fluid levels (it helps to read your car’s oil dipstick properly) or a cooling system issue, and you should see a mechanic.
What does “at oil temp light” mean?
Found in all vehicles with an automatic transmission, the AT oil temp light is the automatic transmission fluid temperature. It helps in regulating transmission oil temperature.
This light works by alerting drivers of escalating transmission fluid temperature. It turns on when your automatic transmission fluid is extremely hot. The at oil temp light is the same across all Subaru and other car models. So, if you are asking what AT oil temp in Subaru Impreza or Forester means, you have your answer.
What does it mean when the “at oil temp” light comes on in the Subaru?
The AT oil temp light coming on your Subaru dash is an indication that your automatic transmission fluid is too hot. Allowing the transmission to cool down should get rid of the light.
It’s important you let it cool, as driving with such hot fluid could result in expensive repairs. The illumination of this light passes the same message across all Subaru. So, for those asking, what does the at oil temp in Subaru Impreza or at oil temp Subaru Impreza mean? Now you know.
How many oil warning lights are in a Subaru?
There are four oil warning lights in a Subaru, all of which help alert drivers to issues in the oil system. This includes the At oil temperatures light, low oil level indicator light, the low oil pressure warning light, and the diff temperature warning light.
At oil temperature light
Instead of a symbol, this alert warning light uses text. If you see the “AT OIL TEMP” light come on in the dashboard, that’s telling you your automatic transmission fluid temperature is too hot.
Olympia Subaru recommends pulling over and parking the vehicle in a safe place immediately. Allow the engine to idle while the transmission cools down, and let this light turn itself off.
You can continue driving once it’s off, but if the light returns, you’ll want a professional diagnosis from one of our techs to find out why your transmission is overheating.
If the “AT OIL TEMP” light begins to flash immediately after starting the vehicle, it could indicate problems with the transmission control module.
Low oil level indicator light
The oil system alert light is supposed to look like an oil can with a drop of oil coming from the spout. Though, to our eyes, it looks a lot more like a genie’s magic lamp.
No matter what this Rorschach test of a symbol looks like to you, an amber-colored oil system light indicates that your engine is running low on oil.
Oil starvation can cause internal engine damage that can require extensive repairs down the road, so be sure to have oil added to the engine as soon as possible when this light comes on.
Driving very long with this light active is sure to cause you major problems, but topping off the engine with oil is cheap, fast and easy.
Low oil pressure warning light
While the warning lights described above are amber in color, this one is red, indicating an even more severe issue. When the genie lamp-looking light comes on in your car, but it’s red instead of yellow, stop driving the vehicle immediately and look into having it towed to a service center.
A red oil system light indicates that the oil pressure in the engine is low. Or, it could be a failed sensor. It’s not wise to leave this one to chance, as low oil pressure in the engine means parts aren’t getting the oil coverage they need to stay protected.
The engine is likely to begin overheating, metal parts may grind against one another, and severe damage may occur. To avoid a nasty repair bill for a complete engine rebuild, stop driving the car as soon as possible when this light comes on.
Rear differential temp light
Exclusive to the Subaru WRX STI, the “R. DIFF TEMP” warning light indicates when the oil lubricating the rear differential is overheating. Once again, we recommend pulling over and letting the differential cool off until the warning light turns off.
Driving with an overheating rear differential can not only lead to damage to the differential itself, but it can also put added strain on the powertrain, causing even more damage. When this light is on, the maximum amount of torque will automatically be directed to the front wheels, overriding any user settings.
Just like the engine oil, your rear differential oil keeps the meshing metal parts lubricated and protected from wear and friction. It also prevents excess heat build-up from friction.
As the oil in the differential ages and breaks down, its lubricating properties will diminish. When this light comes on, it’s likely time to have the rear differential fluid replaced.
Some mechanic and car user discussions
Many find forum discussions useful since they get experts and general car users to answer their questions directly regarding their specific vehicles. However, these forums most of the time only give straight answers and don’t go in depth.
In this article, I have explained in-depth what AT Oil Temp in Subaru means and how to spot if the problem is severe. When the At Oil Temp light is steady, it tells that the ATF temperature is hot due to the car running for a long. This shouldn’t bother you; allowing your transmission to cool should solve the issue.
However, if the light keeps flashing, it’s a serious issue that needs to be taken seriously. Chances are, some faults are in the system. I also explained these, as well as ways to fix them. However, if you want to explore other causes and ways to fix AT oil temp issues related to your specific model, you may want to engage this Subaru AT Oil Temp thread.
What to Do If the Oil Light Comes on in a Subaru?
Step 1: Check the oil level.
Verify the oil level using the dipstick and add oil if it’s low. Refer to your owner’s manual for the correct oil type and viscosity. Also, replace the oil filter if needed.
Step 2: Inspect for oil leaks.
Examine the engine and the ground beneath the vehicle for signs of oil leaks. Address any leaks promptly.
Step 3: Diagnose sensors and the electrical system.
Use a diagnostic scanner to read sensor data and compare it to actual conditions. This can help identify potential issues with the oil pressure sensor or other components.
Test the oil pressure sensor, oil level sensor, and associated electrical circuit to determine if it’s functioning correctly. If necessary, replace the sensor.
Step 4: Inspect the engine oil pump.
If the engine oil pump is suspected as the cause, the engine oil pan may need to be removed for further inspection. Then, install a new oil pump, reinstall the oil pan, and replace the oil and filter.
In case you cannot diagnose or address the issue, contact a Subaru dealership or a qualified mechanic for a comprehensive inspection and repair.
How do you fix it if at oil temp warning light comes on, Subaru?
There are a couple of things you can do depending on what triggered the light. It could be as simple as just letting the car cool or having to fix or change a few things. Here is how to fix at oil temp warning light in your Subaru.
1. Allow the transmission to cool
When you see the warning light, park your car and let it idle while the transmission cools. The light should go after the transmission cools down. Only continue after the light goes off. However, afterward, have your vehicle serviced immediately.
Sometimes, allowing the transmission to cool may be a temporary fix if other factors are responsible. So, how do you tell if cooling the car would solve the issue? Look at the AT oil temp light on your dash. If it appears steady, the ATF is likely hot because you’ve been driving for a while.
So, letting the transmission cool should help. Here, you will not see any code when you check with an OBD II scanner. However, if the light is flashing, there are other things responsible for the transmission overheating. In this case, you may need to fix via other methods below.
2. Change or top transmission fluid
If you are dealing with AT oil temp in Subaru Outback 2013 or AT oil temp Subaru Forester 2014, or any other model, try checking the ATF. Old or contaminated transmission oil can no longer cool down the transmission, hence overheating.
Low transmission fluid levels can also result in parts not getting lubricated enough. This leads to increased friction and, eventually, overheating, causing the light to illuminate. Replace with fresh transmission fluid or top if the fluid looks okay but low.
While some cars require changing or topping transmission fluid every 30k-60k miles, others may run up to 100k miles before needing a top-up. Note that low fluid level can also stem from a leak, so while topping, find and fix the cause of a leak.
3. Use the correct automatic transmission oil
The AT oil temp light flashing in Subaru forester or any other model may be due to the wrong transmission fluid. Subaru works well with certain kinds of oil. While some utilize synthetic blend oils, others use full synthetic oil. Using the wrong oil can cause wear and tear among transmission parts.
Damaged transmission parts often lead to transmission overheating, prompting the warning light to turn on. Switch to the transmission fluid and brand compatible with your Subaru. If you are unsure which transmission oil type and brand best suits your model, consult your owner’s manual.
4. Fix faulty transmission
When transmission parts wear out, they cause overheating in the transmission, triggering the warning light to pop. The only way to permanently put off the light will be to repair or change the faulty transmission. You can, however, prevent transmission failure by carrying out routine servicing —checking fluid level, using correct fluid, etc.
5. Replace dirty or wrong transmission oil filter
As the oil moves through the system, it collects dirt and other impurities, which get trapped in the oil filter. Over time, the filter can get clogged, preventing oil from entering the transmission. This often results in an oil shortage in transmission and eventually overheating, triggering the warning light.
Not using the correct filter can also result in similar issues. Wrong filters often result in leaks from the transmission, causing low oil levels, leading to overheating.
Change the dirty transmission oil filter or switch to the correct transmission filter.
Most manufacturers recommend changing transmission filters every 30k miles or two years. So if your at oil temp in Subaru Outback keeps popping, try checking and replacing the transmission fluid filter.
6. Properly gauge oil level
Excess oil in the transmission prevents lubrication and rotation of the crankshaft, as well as causing high oil pressure. So, ensure you keep the oil level at the recommended line.
When replacing or topping off oil, add a little at a time to prevent too much oil in the transmission. Other issues you may have to tackle are faulty solenoids, transmission modules, etc.
Final Words
The At Oil Temp Subaru refers to the ATF fluid temperature in your Subaru and should appear when the transmission fluid temperature is high. AT oil temp Subaru fix could be as simple as allowing your car to cool. You only need to park and let your car idle while the transmission cools itself.
However, while cooling, the transmission would turn off the light. Get your car serviced immediately afterward. Chances are the light will return if there are underlying issues, putting your engine in harm.