P0741 is a very common OBDII trouble code. It’s know to affect the Toyota Mirai quite often. Here’s what it means:
P0741: Torque Converter Clutch Circuit → Performance or Stuck Off
The Mirai uses a clutch in the torque converter to lock the engine and transmission together at highway speed. P0741 can register whenever this connection is not happening at all or happening properly.
P0741 will not affect the way that your Toyota Mirai’s engine performs at all. It is purely a transmission related code. Although, the engine response may “feel” different without the torque converter locking. It’ll be at a higher RPM, which means that it’ll feel “peppier” for lack of a better term.
See Also: P0700 Toyota Mirai
Toyota Mirai P0741 Defined
The vehicles PCM (Powertrain Control Module) will throw the P0741 trouble code in the Mirai if there is a difference that is greater than 200 rpm between the transmission input shaft and the torque converter speed. This is standard for any Toyota vehicle made on or after the 1996 model year.
With P0741, the code gives you two reasons as to why the code has registered. They are:
- Performance– The clutch, like all clutches, is failing.
- Stuck Off– Somewhere in the Mirai’s wiring, there is an error that is keeping the TCC from engaging. More often than not, this is going to be the issue.
With this knowledge, there can only be so many things that are causing the P0741. We’ll discuss them directly below.
Toyota Mirai P0741 Diagnosis
These are the most common problems that can cause the P0741 in the Mirai:
- Bad Torque Converter Lock up Solenoid– The solenoid that allows the torque converter to lock up is often the culprit. Here’s a good video on how to diagnose and repair the TCC Solenoid. This can be a tough problem for the shade tree mechanic to deal with. It involves a lot of checking for circuit resistance and testing the wiring. That being said, it sure doesn’t hurt to follow the wiring and see if you can find any noticeable issues. Here’s how to use a scanner to diagnose it:
- Bad Torque Converter Clutch– The clutch itself can go bad, just like a manual transmission. The good news is that when this clutch goes out the transmission will still take you to where you need to go. Even if it does so at a slightly higher RPM.
- Short in the TCC– A short in the wiring going from the TCC to the TCM can cause the P0741.
- Bad TCM– The transmission control module itself can be the cause of P0741 in your Mirai. Although, it’s probably not going to be the first place that you should check. The wiring should be the first place that you should check, as it will most likely be the problem.
P0741 Symptoms- Toyota Mirai
Here are the three main symptoms of P0741 in the Toyota Mirai:
- Decrease in MPG– Since the converter cannot lock properly, fuel efficiency will decrease as highway RPM increases.
- Slightly Higher RPM at Speed– Increased RPM at higher speed is usually the most noticeable sign that there is something wrong with the TCC. It’ll feel like driving an older car. Locking torque converters only caught on in the late 70’s.
- Service Engine Soon– Even if there are no other symptoms of the P0741 OBDII code in your Toyota Mirai, the service engine soon light can cause it to fail inspection.
Good luck with the P0741 and your Toyota Mirai. If there is anything that you would like to add, please feel free to leave a comment below.