Experimenting with bypassing the AT 4th gear prohibition when cold - Toyota Yaris Forums

bronsin · 01-03-2012, 10:06 PM

I tried out the mod today and it worked great.

I was at work, .5 mile from the freeway, and it was ~ 30 degrees. Pretty cold for an afternoon high in winter near Philly. Normal winter high ~ 40 degrees.

I started the engine and pushed the button until the Cold Engine Light went out. About 5 seconds. It came back on again after about another five seconds.

I was able to get up to ~ 35 mpg .2 miles before the freeway and it shifted right into 4th with the CEL still on. The CEL went out after .8 mile. So I had .5 mile of 4th gear where I previously would have been in 3rd. This out of a total ~ 6.6 mile trip.

Ive learned to leave my heat OFF when starting out because that dramatically increases the time it takes for the CEL to go out. And note the CEL goes out at 140 degrees of coolant temp which is NOT normal operating temp. (more like 200 degrees)

Also I have the AC fuse pulled so I dont have to worry about running the compressor inadventantly.

Running the defroster on 4 and the heat on max red at 40 degrees gives you a CEL out at 1.3 miles. Thats with my block heater on for 2 hours prior to startup.

Normal miles to CEL out with the block heater @ 40 degrees is .4 mile.

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01-03-2012, 10:06 PM	#19
bronsin Drives: 2009 Base Hatch 2 Dr Auto Join Date: Dec 2008 Location: nj Posts: 4,792	I tried out the mod today and it worked great. I was at work, .5 mile from the freeway, and it was ~ 30 degrees. Pretty cold for an afternoon high in winter near Philly. Normal winter high ~ 40 degrees. I started the engine and pushed the button until the Cold Engine Light went out. About 5 seconds. It came back on again after about another five seconds. I was able to get up to ~ 35 mpg .2 miles before the freeway and it shifted right into 4th with the CEL still on. The CEL went out after .8 mile. So I had .5 mile of 4th gear where I previously would have been in 3rd. This out of a total ~ 6.6 mile trip. Ive learned to leave my heat OFF when starting out because that dramatically increases the time it takes for the CEL to go out. And note the CEL goes out at 140 degrees of coolant temp which is NOT normal operating temp. (more like 200 degrees) Also I have the AC fuse pulled so I dont have to worry about running the compressor inadventantly. Running the defroster on 4 and the heat on max red at 40 degrees gives you a CEL out at 1.3 miles. Thats with my block heater on for 2 hours prior to startup. Normal miles to CEL out with the block heater @ 40 degrees is .4 mile.