Chucksrt

I have this error that I was able to clear but it has come back a couple of different times. Battery voltage reads 13.7 give or take. Are there any trouble areas to look for? I have a tire pressure warning indicator that will not clear and I am not sure if the two are related. My understanding is that this does not use sensors in the tires and relies on speed sensors. If this is correct then all of the tires are properly inflated and the light is still present. This model does not have a reset button under the dash. Could they be related or are there any ways to check the tire system without having to take it to a dealer?

DennisMik

This is from the book. I really know how or what to check.

C1241 LEXUS Description: If there is a problem with the brake actuator assembly (Skid Control Electronic Control Unit) power supply circuit, the skid control ECU outputs the Diagnostic Trouble Code (DTC) and prohibits under the fail safe function. If the voltage supplied to the terminal is not within the DTC detection threshold due to malfunction in such as the battery and alternator circuit, this DTC is stored.

The tire pressure light (TPMS) is not related to this error. It is a good possibility that one of the sensors in the wheels has a battery that is dying. The batteries last maybe 10 years, so this is a possibility. If the sensor is dead, the TPMS light should be flashing when you first turn the ignition on and then be on solid after maybe a minute. Another thing to check is the spare tire. It also has a pressure sensor and could be low on air.

You don't have to take the car to Lexus for this. Your local tire stores can check and see if a sensor is dead. But check prices. We have a chain called Discount Tire that is $61 out the door. We have another one called NTB that is $250 out the door.

Here is a link to the 2006 owners manual. See page 462 for the tire pressure monitoring system.

https://drivers.lexus.com/t3Portal/d...79U-edited.pdf

5W40

Had better using Techstream scan error codes.

If battery, cable connection and alternator are all good then short trip may cause battery juice lower.

My 06 RX330 has indirect TPMS which means there is NO sensors and NO reset button, if your 400h has the same system then check and clean wheel speed sensors first.

Chucksrt

I will check the wheel speed sensors. Although I do not have any other codes for VSC. The error message on the dash is not even listed in the owners manual "check system" with the tire indicator next to it.

Chucksrt

Chucksrt

I will look at the brake actuator and check for voltage and or backed out pins or corrosion at the connector.

dmask0

Hey Chucksrt, did you find a solution to your TPMS issue back in 2018? I think I have a similar issue on a 2008 400H. Thanks

Chucksrt

No. It is my understanding that some of the RX-400h use speed sensors to determine if a tire is low and others use tpms. On my year it could have been either. I sold the car and was never able to figure out what was causing it.