AT Oil Temp in Toyota RAV4 – Dangerous? Fixing the Problem

The problem with several error messages and warning lights is just traditional for the Toyota RAV4. Unfortunately, the actual problem is not always the one that is described in the error message. And it takes quite a while to decode the issue and find the proper solutions. This is true for new Toyotas and also for older RAV4 models that already have some miles on them.

AT Oil Temp light highlights

• Common reasons:AT fluid hot, AT slipping
• How to fix:stop the car, let it cool down, try driving
• Possible consequences:AT fatal failure is possible
• Priority level:High
• Can you drive?Carefully
• DIY repair:Impossible
• Repair price range:$400-$4,500

Toyota RAV4 says "AT Oil Temp" - what's this?

This problem is very often reported for older RAV4 models. Especially, the SUVs made from 2001 to 2003. But even the new Toyotas still can surprise you with this warning message on the dash.

Originally, this message was introduced by engineers to warn the driver that the transmission in the car is too hot and needs some time to cool down. The transmission may or may not have the temperature sensor depending on the year. The decision about the hot transmission is often made by the ECU using different factors.

This explains why sometimes your RAV4 may show this message while the transmission temperature is completely OK. Something else may be wrong and it may fool the ECU into thinking that the transmission is slipping and the AT fluid is too hot.

If the temperature sensor is present in your model of transmission, it should send readings of 300 degrees F to the ECU so that it launches this message. This temperature is threatening and if you keep driving and ignoring this warning light, you may eventually get a totally destroyed automatic transmission that requires replacement.

Some symptoms that come along with the AT Oil Temp light

It's important to register all the possible symptoms that accompany this light. It's not uncommon that the AT Oil Temp light is triggered by some other serious problems in your car like the issues with the ignition that cause engine misfiring. The sensors may take engine misfires for transmission slipping and eventually light up the warning light to inform you about the high temperature of the transmission fluid.

Here are the symptoms you may encounter:

• Slipping of the transmission. You press the gas pedal and the engine revs up immediately, but the speed of the car doesn't change or changes very slowly.
• Transmission shudder. This will be especially noticeable at idle. When you are at the traffic light and the car is idling, the shudder will become the vibration that affects the entire vehicle.
• Engine stalling. If the problem with the transmission is very serious, the engine may stall because it will become too hard to rotate the torque converter.
• Check engine light. This light may be triggered by several different codes and knowing these error codes will obviously help you identify the initial problem.
• Engine hesitating and sputtering. This will often occur when the engine has some other problem that also triggers the fluid temp warning light in your RAV4.

You need to register all the symptoms and remember them. When you tell the mechanic about these symptoms, they will easily identify the primary reason for the problem in your car. At least, this will take less time and the initial problem will be located sooner. Of course, this will affect the overall costs.

By the way, mechanics say that in older RAV4 models, the AT Oil Temp warning light could have been triggered by a lot of engine problems, not just by the issues with the transmission. Keep this in mind when you are trying to locate the issue.

What are the actual reasons for the AT Oil Temp light?

As you already know, the problem that triggers this light may not only come from the transmission. This can be the issue with almost any component of the engine that affects the work of the transmission and may make the ECU think that this issue can have something to do with the gearbox.

Here, I've compiled the list of things that can trigger the AT Oil Temp message in your Toyota RAV4:

1. Transmission fluid temperature is high

This may happen when the temperature goes up to 300 degrees Fahrenheit. Such a temperature is dangerous for the life of the transmission and can just kill it after some time. The reasons for this may be the problems with the transmission or just off-roading when the transmission has to work hard and keep a lot of load on it.

2. Transmission slipping

When the transmission starts slipping, the ECU spots this and may immediately throw this message. The slipping may occur because of the worn-out components of the transmission and also old fluid that can no longer do its job well.

3. Low or bad transmission fluid

This is a serious thing to check and fix as soon as possible. The fluid in your transmission has to be changed about every 40K miles. If it works for more time, it will deteriorate and become ineffective. In an automatic transmission fluid plays a huge role in the overall functioning of the transmission, so the light may illuminate.

4. Electrical problems

Wiring and connections may go bad, especially if your RAV4 is quite old and/or has a lot of miles on it. In this case, the problem may be connected with the lack of the needed readings and the ECU may decide that something is wrong with the transmission. One of the wires may have fallen off or corroded in the spot of connection. This will obviously trigger issues with the transmission work because the ECU doesn't get the proper information about the gearbox.

5. Engine problems

Among the most common engine problems that can trigger the AT Oil Temp warning light in the RAV4, I should point out all the issues that cause misfiring. If your engine misfires because of, say, bad spark plugs and ignition coils, you may see the AT Oil Temp light eventually on the dash. The ECU is fooled by misfiring and may make the conclusion that the transmission is faulty and needs repair.

The misfiring engine is important to check before you allow mechanics to change the fluid in the transmission and do some other things that will cost you a fortune.

How can you solve the AT Oil Temp problem in your Toyota?

This is the problem you can easily solve if you know the reason. But for a person without proper technical knowledge and experience, it's extremely hard to find the reasons, so you will most likely want to go to a good shop and have the vehicle inspected properly.

Still, there are several things you can do on your own to reduce the overall costs for repairs:

• first of all, register all the symptoms so that your mechanic can easily locate the problem;
• also, you may get an OBD2 scanner and read the codes, then google these codes and see what's wrong with the car;
• if your transmission has a dipstick, check the fluid level before doing anything else;
• also, look at the fluid on the dipstick - if it's dark and smells bad, you should have the fluid changed as soon as possible;
• let your car rest for 20-30 minutes, then start it again and drive - will the warning light appear again?

If you can't locate the problem or can't solve it on your own, then you should plan your visit to the repair shop.

Can you drive when the AT Oil Temp light is on?

I don't recommend driving when this light is on your dash. First of all, you may need to stop and let your car rest for a while. This will help the fluid cool down and you will be able to safely drive several miles. If the light is not off even after a long rest, you should stop the vehicle and try to find the reason.

In some cases, it's cheaper and better to call a tow truck than to kill the transmission.

Final thoughts

You should understand that the problems with the automatic transmission are very serious and can cause a lot of problems. First of all, you need to understand why the AT Oil Temp light is on in your Toyota RAV4. Sometimes, it's all about the transmission, but very often, the problem is hidden in the engine.

You can drive further only after you locate the issue and understand the reason for this problem. Driving your RAV4 with this light illuminating is not the best idea you can have.