Good day all. I am a new owner of a previously experienced RX330. I am reading an OBD code B1400 and I am unable to nail down a cause of this code. The usual internet search has offered up such things as a broken MAS air sensor, and Transmission Engaged At High Throttle Angle. I searched this forum for any data and came up empty. The vehicle has 96,059 miles, runs perfect, starts without any real issues, and I am experiencing about 22 MPG driving back and forth to work on surface roads with minimal stops and starts. Thank you in advance for insight you can offer.

 

I did a google search on lexus B1400 and got this result - ( http://b1400.enginefaultcode.com/lexus-rx )

Here are some excerpts:

While fuel economy was increased, acceleration was seriously compromised, and the loss of engine vacuum led to a dangerous loss of braking assist when the B1400 code system was in four-cylinder mode.

it would probably be worthwhile to carefully inspect the wire harness near the intake manifold bracket. This is done most easily from below the car in the area near the oil filter.

 

Thanks DennisMik for that link.