What Does The 'AT Oil Temp' Light Mean On A Subaru?

Over the years, Subaru has developed a reputation for manufacturing some of the most reliable cars and SUVs on the road. But even vehicle's boasting solid reps like the SlashGear-approved 2024 Outback are susceptible to the occasional hiccup or breakdown that can lead to a pricey visit to the mechanic. As with most automobiles on the market these days, some of the more potentially problematic issues your Subaru may run into might be avoided by simply paying attention to the various warning lights designed to alert you to them. 

Of course, nobody wants to see a warning light illuminate in their dashboard display, as that generally means a trip to the mechanic is unavoidable. However, warning lights in your Subaru do serve a vital function in alerting you to problems, and should therefore never be ignored. That's particularly true of the one proclaiming "AT Oil Temp," which, if you're unfamiliar with it, is indeed an important one, as the "AT" stands for Automatic Transmission. 

It should go without saying that any issue that effects your vehicle's transmission should be considered major. The "AT Oil Temp" light is programmed to turn on in Subarus when the onboard computer registers that the vehicle's transmission fluid is too hot, though it may also begin blinking off and on if there's a malfunction in the transmission control module. In the case of overheated transmission fluid, the issue can lead to increased friction in the shifting gears, and possibly even transmission failure.  

Given the stakes, you will want to take action as soon as possible if the "AT Oil Temp" light turns on in your Subaru to avoid catastrophic damage to the vehicle's transmission. To that end, it is recommended that the first course of action you take if that light illuminates in your dashboard display is to find a safe place to pull your Subaru off the road and allow the engine to idle until it completely cools down.

If you're unsure how to tell if the engine has cooled sufficiently, the most obvious sign will be if the "AT Oil Temp" light turns off. Once that has happened, the vehicle will likely be safe to drive again. It might be a good idea to try and check your transmission fluid before you get back on the road to ensure low fluid is not the cause of the problem. In any case, you will want to be careful if you continue to operate the car once it's cooled off, and if the warning light should happen to click back on again, further action will be necessary.

Yes, that means you will need to take your Subaru to a licensed auto technician so they can diagnose and fix the overheating issue. You should familiarize yourself with your vehicle's warranty and/or service plan before you do so, however, because if the repair is covered, getting the car to a certified Subaru tech is the way to go.

Just FYI — there are a few other warning signs apart from the "AT Oil Temp" to keep an eye out for if you're concerned about overheating transmission fluid and the issues that it can cause. One of the clearer indications that your transmission fluid may be overheating is the presence of a burning smell when your engine is on, which will likely become more prevalent the longer the vehicle operates.

Another common sign of an overheated transmission is the regular presence of leaking transmission fluid. New transmission fluid is typically reddish in color, but can darken over time depending on levels of contamination. So, if you're seeing fluids under the car in the driveway that are red, pink, or somewhat dark brown in color, it's likely transmission fluid. Said fluid may be leaking because the transmission has been overheating, with the excessive heat and pressure damaging the seals and gaskets therein to the point that they are failing.

That particular issue may be caught early by simply adding routine transmission fluid checks to your vehicle maintenance routine. In some cases, an overheated transmission can lead to other issues with your car, which may result in unusual noises, gear slippage, and a noticeable vibration in the vehicle's shifting mechanism. As is the case with all the other bells, whistles, and warning signs we've covered here, if you are experiencing any of these issues in your Subaru, you will need to have the issue checked out by a licensed professional sooner rather than later.