Transmission Temperature Light on a Toyota Mirai
Have this checked promptly. It is not an immediate stop, but do not ignore it for long.
What the Transmission Temperature Light Means on a Toyota Mirai
The transmission temperature light on a Toyota Mirai warns the gearbox fluid is overheating. Hot fluid loses its protective properties fast, so this is a stop-and-cool situation to avoid serious transmission damage.
How Urgent Is the Transmission Temperature Light?
How worried should you be? For the Transmission Temperature Light on a Toyota Mirai, the urgency is high. A good rule technicians rely on is 'colour plus behaviour': match the warning colour against how the car is actually performing. If the Toyota Mirai still drives normally and the light is steady, you usually have time to plan a proper diagnosis; if performance drops or the light flashes, err on the side of caution and stop safely.
Common Symptoms Alongside the Transmission Temperature Light
Alongside the Transmission Temperature Light, Toyota Mirai owners commonly report a handful of related signs. Some are obvious, others easy to miss until you pay attention. Keeping a short mental (or written) log of what the Toyota Mirai does when the light is on gives whoever performs the repair a huge head start and can save you money on diagnostic time.
- Transmission temp warning lit
- Delayed or harsh shifts
- Burning smell
- Transmission slipping under load
- Often appears when towing or climbing hills
What Causes the Transmission Temperature Light to Come On?
Why did the Transmission Temperature Light come on in your Toyota Mirai? The honest answer is 'it depends', but the possibilities cluster into a recognisable set of causes. Knowing them in advance means you will not be caught off guard by a diagnosis, and it lets you sanity-check any repair quote against what commonly goes wrong on the Toyota Mirai.
- Heavy towing or load
- Low transmission fluid level
- Old, degraded fluid
- Blocked transmission cooler
- Stuck thermostat or failing pump
How to Fix the Transmission Temperature Light on a Toyota Mirai
To resolve the Transmission Temperature Light on your Toyota Mirai, resist the urge to simply disconnect the battery and hope it stays off. A warning that is cleared without addressing the cause almost always returns. The step-by-step approach below is the same logical order a professional follows on the Toyota Mirai: confirm the basics, read the stored codes, then target the actual fault.
- Pull over safely and let the transmission cool with the engine idling in park
- Reduce load and avoid stop-start driving until cool
- Check transmission fluid level and condition
- Have the cooler and fluid inspected
- Service the fluid or repair the cooling circuit as diagnosed
Is It Safe to Drive With the Transmission Temperature Light On?
Whether it is safe to keep driving your Toyota Mirai with the Transmission Temperature Light on comes down to urgency (high) and behaviour. As a rule, if the light is red or flashing, or the Toyota Mirai is running poorly, stop somewhere safe and arrange help rather than pushing on. If the light is amber and the car drives normally, you generally have time to reach a workshop — but 'have time' is not the same as 'ignore it', so book a check promptly.
Diagnostic Trouble Codes Linked to the Transmission Temperature Light
If you scan a Toyota Mirai showing this light, these are the OBD-II trouble codes most commonly associated with it. The code you actually retrieve is what pinpoints the repair.
| Code | Meaning |
|---|---|
P0700 |
Transmission Control System Malfunction A general request from the transmission control module indicating a stored transmission fault. |
P0740 |
Torque Converter Clutch Circuit Malfunction The torque converter lock-up clutch circuit is not responding correctly, affecting shifting and economy. |
Professional Mechanic Tips
If this light appears while towing with a Toyota Mirai, pulling over and idling in park (not off) lets the fluid circulate and cool fastest.
Burnt-smelling, dark transmission fluid is overdue for a change — old fluid is a leading cause of overheating.
Frequently Asked Questions
Why is the Transmission Temperature Light on in my Toyota Mirai?
Your Toyota Mirai turned on the Transmission Temperature Light after its self-diagnostics flagged an issue in that system. Because several different faults can trigger the same symbol, the smart first move is an OBD-II scan to pull the specific code before you spend any money.
Can I keep driving with the Transmission Temperature Light on?
It depends on the urgency (high) and how your Toyota Mirai is behaving. If the light is red or flashing, or the car drives differently, stop safely and get help. If it is amber and everything feels normal, you can usually drive to a workshop soon — just do not put off the diagnosis.
How much does it cost to fix the Transmission Temperature Light on a Toyota Mirai?
Repair cost for the Transmission Temperature Light on your Toyota Mirai depends entirely on the root cause. Because the same symbol covers cheap and expensive faults alike, a proper scan-based diagnosis is the best money you can spend — it turns a guess into a precise, fair quote.
Will the Transmission Temperature Light reset itself on a Toyota Mirai?
Sometimes the Transmission Temperature Light on a Toyota Mirai clears on its own once the condition that triggered it no longer exists — for example after several good drive cycles. More often, though, the light stays on until the underlying fault is repaired and the code is cleared, so treat a self-clearing light as a reason to still investigate.