mdttoyotech/TikTokA mechanic has said that a flashing Check Engine light on a 2025 Toyota Tundra pickup truck is a perfect example of why nobody should skip any of the basics when it comes to car maintenance. Mechanic and TikTok user @mdttoyotech posted a video on his account to explain why he believes this.According to the TikTok user, it only took a quick visual inspection of the Toyota for him to find out what was wrong with it. The mechanic also said that if you don't do these basic inspections, you could end up wasting a lot of your own time.He also said this comes down to him being a flat-rate technician, so you will want to save as much time as possible while ensuring that you do a good job. The video also showed the mechanic checking for faults on the Tundra via a computer system.AdvertisementAdvertisementWhile the check on the computer was running, he then proceeded to do his visual inspection. It was this that ultimately revealed the problem and showed how helpful just a quick look around a vehicle could be. Had he not done so, it could have taken an age to find the problem.What Was Wrong With the 2025 Toyota Tundra?According to @mdttoyotech, the 2025 Toyota Tundra had come into his shop with just 7,000 miles on the odometer. It was as it came in that he noticed the flashing Check Engine light, so he got the Toyota pulled into the bay to take a closer look at the pickup truck."When you're a flat-rate technician, you want to save as much time as possible," he said in the video. The mechanic then connected a computer to the truck to scan it for any issues. During this, he also did a visual inspection, and he then found that the gas cap had been left loose at the rear of the Tundra. This was why the Check Engine light had come on."If the gas cap is left loose or off, it will set a thing called an emissions EVAP leak," explained the mechanic. "This is where fuel emissions are somehow leaking out of the system from an unsealed part of the fuel system, mainly an emissions thing for the government in the environment," he added. So, as he showed, the visual check saved him a lot of time and allowed a faster diagnosis of the problem.It Doesn't Take Much To Cause an Engine Light To Flashmdttoyotech/TikTokAs it transpires, it really doesn't take much to have a Check Engine light come on and flash. A loose or damaged gas cap can be the reason behind this. Modern vehicles are designed to stop fuel vapors from escaping, thanks to evaporative emissions systems. If the cap is loose and doesn't seal properly, the system can then detect a leak, thus triggering the warning.AdvertisementAdvertisementOf course, a loose gas cap won't always be the reason for the warning going off. There are a myriad of minor and serious issues that could lead to the Check Engine light coming on. Diagnostic tools can often help track that down, but luckily with this 2025 Tundra, the problem was indeed the loose gas cap.If you want more stories like this, follow Guessing Headlights on Yahoo so you don't miss what's coming next.