Transmission Light On Car – Meaning, Causes & Fixes

The transmission is as important as the car engine because the vehicle cannot move without the transmission. However, most people prioritize the engine over the tranny. And this is why most drivers are familiar with that panic-inducing check engine light but have not heard of transmission warning light.

Although the transmission light on car does not appear often like the engine warning light, unfortunately, older cars do not have this feature. For vehicles that do not have this feature, the transmission will likely leave you stranded in the middle of nowhere when it fails without any signs.

The only signs you may have is a lack of acceleration or an unresponsive gas pedal. Since engine-unrelated issues can be the culprit, you may not know the transmission is bad until the vehicle stops moving. Latest model cars have a transmission warning light that pops up on the dashboard whenever the tranny malfunctions.

what does a transmission light look like

What does it mean if the transmission warning light on car

Transmission warning light on VW and other car models can come on for several reasons. If the warning light appears on the dashboard, something is wrong with your automatic or continuously variable transmission or the related components.

If the transmission light came on while driving, it could mean there’s an issue with the overdrive or traction control light, or the tranny is overheating. Although it could be a warning indicator for several transmission-related issues.

It’s important to note that if the transmission light came on then off on some vehicles, it doesn’t mean there’s a problem. It could be a service reminder for tranny maintenance. For instance, it could mean the tranny fluid is low and needs replacement. If that is the case, adding more fluid will erase the warning light.

If the transmission lights pop up due to a transmission problem, the vehicle will project some symptoms that’ll help you track the leading cause. Let’s see the probable causes in the following paragraphs.

Causes of transmission warning light

Like the check engine light and other warning light cases, several factors can cause the vehicle to trigger the transmission warning light. Here are the possible causes to check when this light illuminates on your dashboard.

Low transmission fluid

The transmission fluid lubricates and cools the internal tranny components. If the fluid gets low, it’ll cause excessive overheating, friction, and wear on the internal parts, eventually leading to catastrophic damage.

Your powertrain control module (PCM) or transmission control module (TCM) will recognize the abnormal operation and project the transmission warning light on Honda Pilot or your respective car model for you to take necessary precautions. It is important to note that a low transmission fluid usually shows there’s a leak somewhere.

Transmission overheating

Overheating transmission is the common cause of a transmission warning light. Aside from low transmission fluid, other issues like internal system failures, obstructed transmission coolers, and towing heavy loads can cause the tranny to overheat. 

Internal system failure

Continuous variable and automatic transmissions are complex machines with several components. If any of these components fail or wear out, the system will not function as predefined by the manufacturer. Once the system detects a malfunction, it’ll project the transmission warning light on the dashboard to notify the driver of what’s happening.

Lousy torque converter

The torque converter is a fluid coupling device between the transmission and the engine in continuous variable and automatic transmissions. The converter has a lock-up clutch that mechanically links the transmission and the engine based on the driver’s command.

With time, the torque converter may fail and cause issues like transmission slipping or shuddering. When this happens, the TCM will notify the driver of underlying issues by triggering the transmission warning light on Ford Ranger or your respective car model.

Valve body issues

Most automatic and CVT transmissions have valve bodies. The valve body has multiple fluid passages that send fluid to every nook and cranny of the tranny. If the valve body malfunctions, the fluid transportation process will be compromised. If this happens, the TCM will trigger the transmission warning light on the dash.

Lousy shift interlock

The transmission warning light doesn’t necessarily mean you have a transmission problem. For instance, a transmission warning light on BMW could mean the shift interlock is bad. The shift interlock is a feature in cars that prevents automatic transmission cars from getting out of ‘Park’ without depressing the brake pedal.

Faulty computer controls

The powertrain control module collects data from various car sensors. If any transmission-related sensor fails, it could send false information to the car computer, causing it to trigger the transmission warning light on the dashboard. Other issues like faulty shift solenoids and burnt, damaged, or frayed wires can cause the illumination of the transmission warning light.

What to do if transmission light on car

You have to stop and pull over if the transmission warning light comes on while driving. However, you need to be sure of your surrounding – do not stop in the middle of nowhere. If you’re at a lonely place when the light pops up, continue driving until you get to a gas station or where people live. However, since you’re not a mechanic, it’s safe to contact your mechanic to tow the car to his garage.

As explained above, it could be low tranny issues, faulty car sensors, or damaged wirings. These are pretty inexpensive to fix. In any case, here’s what you should do if you love trying out things yourself.

Pull over and turn off the engine. Then, allow the tranny to cool for five to ten minutes. After that, locate and remove the transmission dipstick. Then, clean the dipstick and put it back in to check the fluid level.

If the dipstick is below the recommended level, get the right fluid and top it. But if the fluid is at the right level, you need to have a mechanic track the leading cause and proffer a solution to the problem. 

How to fix transmission light on car

A transmission is a complex machine that requires experienced technicians to diagnose and rectify issues. Therefore, the best solution when a transmission light comes on is to check the tranny fluid and top it if needed. You need to consult your mechanic if the culprit falls outside the transmission fluid.

The mechanic will start by diagnosing the vehicle with a scan tool. From there, he’ll know whether it is external issues like lousy sensors, damaged wirings, interlock shift problems, or internal issues. Next, the technician will have to drop the transmission and disassemble it if it is an internal issue. After that, he’ll find and replace faulty internal components.

check transmission light

Frequently Asked Questions – FAQs

Q: What does a transmission warning light look like?

How does the transmission warning light symbol look? Not all cars use the same transmission warning light to alert you when the system detects underlying issues. Some cars have unique tranny warning lights, depending on the year, make, and model.

For instance, your vehicle may use different warning lights to notify you in case of transmission problems. The system may throw up a service engine light, traction control light, or an overdrive warning light. This makes it challenging to figure out when the system illuminates a transmission warning light on Toyota and other car models without consulting your service manual.

Q: Can you drive with the transmission light on?

Since several factors, including minor and significant problems, can trigger the transmission light on the dashboard, it is not ideal to continue driving with it. Even if your neighbor has been driving with transmission lights for over a thousand miles, do not drive with it. A malfunctioning interlock shift could be the culprit in his case, which does not affect the tranny.

In contrast, the light may appear on your dashboard due to transmission shuddering, slippage, overheating, excessive friction, or other internal transmission issues. If this is the case, you’ll ruin the transmission if you continue driving with the warning light.

Q: What does the yellow transmission light mean?

The yellow transmission temperature light means the tranny is overheating or one or more of the internal components is reaching a critical point. This is commonly caused by excessive metal shavings in the tranny due to friction, low transmission fluid, heavy towing, or other serious issues.

Q: How serious is a transmission light?

The transmission warning light on Ford Focus and other car models can be a simple service reminder, telling you to change your transmission fluid. However, it can also indicate severe internal transmission component problems. Therefore, you need to check the transmission light and rectify the problem or do the required maintenance. So, the transmission warning light can be a severe case or a minor issue.

Q: Will check engine light come on if transmission fluid is low?

The check engine light is one of the common symptoms of low transmission fluid. So, it’s important to check the transmission fluid level when the engine warning light displays on the dashboard. You may be wondering, what’s the difference between a transmission light vs. check engine light?

The transmission light comes up whenever the car computer detects issues related to the transmission, while the check engine light comes up whenever the system detects engine-related issues. However, both lights can appear on the dashboard whenever you run out of transmission fluid.

Final Words

Sometimes, the transmission fails without giving you enough room to prevent things from going south. But with the transmission light on car, you have to find and fix the root cause of the light before it drops expensive repair bills on the table.

While the transmission light may not always point to a problem, do not ignore it for any reason. It could be that you have a critical issue at hand. You won’t want to face expensive repairs when you can avoid them.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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