One of the most common trouble codes with the Toyota Mirai is the P0496 code. This code number references a number that is given to you when you plug your Mirai into an OBDII scanner.
Below, you’ll find the most common symptoms and ways to diagnose the P0496 in your Toyota Mirai. Good Luck!
Toyota Mirai P0496 Symptoms
P0496 code in the Toyota Mirai will often be accompanied by an erratic idle. The engine will rev up and down trying to find the proper idle speed. This will often happen right after you buy gas. It also might not start at all at the gas station.
If you’re old enough to have driven a carbureted vehicle the old stomp the gas and crank the engine method does actually help start the car. This is due to the air fuel mixture being off.
Related: P0420 Toyota Mirai
Toyota Mirai P0496 Meaning
P0496 is a universal OBDII trouble code. This means that regardless of which make or model of vehicle, the code will mean the same thing. The code technically stands for:
Evaporative Emission System High Purge Flow
The EVAP system captures all fuel vapor from the fuel tank and sends them to the engines intake in order to be ignited in the normal combustion process.
When the Toyota Mirai computer detects that the EVAP system is purging when it should not be, it will throw the P0496 OBDII code.
Toyota Mirai P0496 Causes
There are many things that can cause the P0496 trouble code on the Toyota Mirai. Here are the most common problems that will throw the code.
Vapor Canister Purge Valve– The most common culprit with the P0496 trouble code and the Toyota Mirai is going to be the vapor canister purge valve. When it goes bad, it typically causes issues with the vehicle’s idle speed. This is especially true right after you fuel up the vehicle.
It’s really easy to replace. There are a few clips that you need to find and remove. There is a a great YouTube video on diagnosing the problem below.
PCM– It is possible that the engines computer system itself has gone bad and is registering a P0496 when it shouldn’t be. But, this is definitely not where you want to start.
Wiring– It is possible for shorts in the wiring harness leading to the Vapor Canister Purge Valve has gone bad. Check it.
Fuel Cap– A bad fuel cap can cause the P0496 code to be thrown for sure. Often, you’ll get a message informing you that the fuel cap is off even when it is on. If you are getting that message, plus a P0496 on your Toyota Mirai, it may save you a ton of time and money to replace the fuel cap and see if it goes away.
Fuel Tank Pressure Sensor– If the fuel tank pressure sensor has gone bad, it can cause all sorts of problems, including the P0496 code.
Here’s a good video on it:
Good luck figuring out what is wrong with your Mirai. We hope this helps. If there is anything that you feel like you could add, please feel free to leave a comment below.