Temperature is a vital factor in car engineering. There’s a reason why your car has different coolant fluids and other cooling mechanisms. Without proper cooling, the transmission system and the engine will overheat. The AT oil temp is present in all automatic cars, such as Subaru models, and regulates transmission fluid temperature.
Along with the transmission temperature gauge, the AT oil temp light indicates the transmission oil temperature. Though, there’s a slight difference in the functions of both indicators.
The transmission temperature gauge shows you the all-time temperature status of your transmission system. However, the AT oil temp light only comes on when the transmission oil has gotten hotter than usual.
Now, let’s dive into the meaning of AT oil temp in Subaru models, the possible causes, symptoms, and solutions.
What does “at oil temp light mean”?
The “AT Oil Temp” light in Subaru vehicles serves as a crucial indicator of the health and functioning of the automatic transmission system.
When this light illuminates or blinks, it alerts the driver to potential issues concerning the transmission’s temperature or the condition of the transmission fluid.
This warning should not be taken lightly, as it can signify a range of problems, from low fluid levels to more severe transmission malfunctions.
Immediate attention to this signal is essential for preventing further damage to the transmission, which can be costly to repair and detrimental to the vehicle’s overall performance.
Understanding and responding promptly to this warning light is key to maintaining the longevity and reliability of a Subaru’s transmission system.
How many oil warning lights are in Subaru?
There are four oil warning lights in a Subaru, all of which help alert drivers of issues in the oil system. This includes the At oil temperatures light, low oil level indicator light, low oil pressure warning light, and diff temperature warning light.
#1. At oil temperature light.
This light appears as a text on your dash reading “AT oil temp light or AT oil temp light.” This is the vehicle telling you that the automatic transmission fluid is hotter than usual.
The At oil temp light may illuminate or blink for several reasons. However, light blinking immediately after starting the vehicle often points to issues with the transmission control module.
#2. Low oil level indicator light.
The low oil level indicator is an amber-colored genie-looking lamp that appears on your dash.
And sometimes it looks like an oil can dripping oil. The illumination of this light is a telltale sign that your engine oil level is too low and needs topping to avoid severe engine damage.
#3. Low oil pressure warning light.
The oil pressure is a red-colored-looking genie lamp. The illumination of the light indicates that the engine oil pressure is low or the sensor is failing.
Low oil pressure means your engine parts are not getting the right amount of oil to keep them protected.
As such, the engine components may rub against each other and eventually overheat. Addressing this light seriously will help prevent permanent engine damage.
#4. Rear differential temp light.
The Rear differential temp light is an amber color light and turns on when the rear differential oil is overheating.
The R differential oil helps lubricate the rear differential to keep the rotating parts lubricated and protected from excess friction, wear, or tear.
When it is old or contaminated, it loses its lubricating properties. This not only harms the differential but also strains the power train, resulting in more harm.
When this warning light comes on, stop your vehicle and park for a while so the differential oil cools off.
You can continue your journey when the light goes off. You should, however, check the differential oil and replace it if it has aged or is too dirty. Not tackling the cause may result in the light returning.
Symptoms of AT Oil Temp Light Flashing Subaru
- Difficulty in Shifting Gears: One of the most noticeable symptoms is a change in the way the transmission shifts between gears. This might manifest as hesitation, rough shifts, or an inability to change gears smoothly. In severe cases, the vehicle might not shift gears at all.
- Transmission Slipping: This occurs when the transmission spontaneously slips in and out of gear while driving. It can feel like you’re driving in a certain gear, and then it changes for no apparent reason, or the car struggles to accelerate.
- Overheating Transmission: An overheated transmission can cause the AT Oil Temp light to come on. This might be accompanied by a burning smell, which clearly indicates that the transmission is running too hot.
- Unusual Noises: Whining, clunking, or humming sounds coming from the transmission are not normal and could indicate that the transmission fluid is either low or contaminated. These sounds may become more pronounced when shifting gears.
- Reduced Fuel Efficiency: When there’s a problem with the transmission, such as low fluid levels or overheating, the vehicle may exhibit reduced fuel efficiency. This is because the transmission isn’t operating optimally, requiring the engine to work harder.
- Transmission Fluid Leak: If you notice a red, sweet-smelling fluid under your car, it could indicate a transmission fluid leak, which can lead to low fluid levels and trigger the AT Oil Temp light.
- Check Engine Light: Sometimes, the check engine light may also come on along with the AT Oil Temp light, indicating that there are additional engine or emission system issues that need attention.
- Erratic Transmission Behavior: You might also experience erratic behaviors such as sudden jerking or stalling, especially when the vehicle is first started or during shifting.
It’s important to note that these symptoms may vary based on Subaru’s specific model.
Causes of Subaru AT Oil Temp Light
If you see an AT Oil Temp light on your Subaru’s dashboard, you may have pushed your Subaru too hard.
It could also be caused by low transmission fluid, the wrong type of fluid, or a bad transmission fluid temperature sensor. Other options include defective wiring, a slipping transmission or a bad transmission oil pump.
Any one of these causes is serious and should be remedied before driving any further.
#1. Overheating Transmission (Hard Driving).
Subaru vehicles are meant for some extreme adventures. However, there’s always a chance that you’ve pushed your vehicle too hard.
If you are towing heavy loads, climbing steep inclines or tearing up the trail, you may have overworked the transmission. Thankfully, if you stop immediately and let the transmission cool off, you may not have any repairs to make.
#2. Low Transmission Fluid Level.
When you run the Subaru with low transmission fluid, it can cause serious consequences to your vehicle. First, it’s going to overheat the transmission because of the lack of lubrication.
In normal driving situations, the Subaru shouldn’t have low fluid. If it does, you may consider that the system is leaking somewhere.
To prevent this problem from occurring again, you need to not only fill the transmission back up but also fix the leak that’s causing the low fluid.
#3. Wrong Transmission Fluid Used.
There are different types of transmission fluid available. It’s important that you put the right type in your vehicle or it could lead to problems.
For most vehicles, Subaru recommends using Subaru ATF HP or Dexron III in the transmission.
Using the wrong one for your vehicle can lead to serious consequences, possibly even transmission failure. It can also cause the AT oil temp to start flashing.
#4. Bad Transmission Fluid Temperature Sensor.
If the sensor designed to check the fluid temperature fails, the readings will be inaccurate. The first sign will be a flashing light, indicating that something is wrong with the system.
You may also notice the transmission not shifting as it normally would because adjustments aren’t being made properly. In severe cases, the car can go into limp mode to protect the transmission.
#5. Bad Wirings.
The transmission is a mechanical part, but it’s made up of many electrical connections. Between every sensor and the transmission is an electrical connection that needs to be in good working order to communicate.
If some of the wiring or a connector fails or breaks, it can cause communication to cease. What you’ll get in return is a flashing AT oil temperature light.
#6. Slipping Transmission.
Normally, a slipping transmission is a sign of a larger problem. The transmission could be slipping because of a failing clutch pack.
It’s also possible that there are hydraulic circuit problems. Furthermore, any of the issues we’ve already discussed could lead to a slipping transmission too.
Whatever the cause, when the transmission starts to slip, the oil can heat up and cause this warning light to blink.
#7. Bad Transmission Oil Pump.
The transmission oil pump is responsible for circulating the fluid in the transmission. When it fails, the transmission won’t get the lubrication it needs and it will overheat.
You may start to hear a whining noise or experience slipping. Once the pump fails completely, you may not be able to get the transmission into any gear.
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 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 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 dirty transmission oil filter or switch to the correct transmitter 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 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.
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 times 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 car running for 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.
These I also explained 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 Subaru thread.
Preventative Measures For Your Subaru’s Transmission
Keeping your Subaru’s transmission healthy is key to its long life and reliability. Regular maintenance helps your Subaru run smoothly and prevents problems like the AT Oil Temp light flashing.
By being proactive, you can keep your car in great shape and enjoy better driving.
The Role of Regular Maintenance
Having a regular maintenance plan is vital for your transmission’s health. Here are important steps to take:
- Regularly check the transmission fluid levels and condition.
- Change the fluid as recommended by the manufacturer.
- Inspect the transmission parts and connections often.
- Watch for any signs of transmission trouble and fix them early.
By focusing on preventive maintenance, you greatly help keep your transmission in good shape.
Knowing and following these steps will make your drives smoother and could save you from expensive repairs later.
FAQs.
Q: What does a flashing AT Oil Temp light indicate in Subaru vehicles?
A flashing AT Oil Temp light means the transmission fluid might be too hot. This can cause serious damage if not fixed quickly.
Q: How can I troubleshoot the flashing AT Oil Temp light?
First, check the transmission fluid levels and its condition. Make sure it’s at the right level and look at its color and smell. If it’s dirty or low, you might need to flush and replace it.
Q: When should I seek professional help for a flashing AT Oil Temp light?
If the light keeps flashing after you’ve checked the fluid, or if you see other warning lights and the car isn’t running right, get a pro to check it out.
Q: What fixes can be performed to address the flashing AT Oil Temp light?
Fixes include flushing and replacing old transmission fluid. You might also need to check and replace faulty solenoids to keep the transmission cool and working well.
Q: Does Subaru offer warranties for transmission issues?
Yes, Subaru has extended warranties for some CVT problems. They cover repairs or replacements for up to ten years or 100,000 miles, depending on your car.
Q: What are common repairs needed for the AT Oil Temp light issues?
Common repairs include replacing the transmission control valve and checking for damage to the valve body. Both are key for keeping the fluid flowing right and the transmission running smoothly.
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.