bowen.chau

After I have removed the EFI for 5 minutes and test drove again. The problem still occurs. It happens only after the engine has been warmed up, like driving after 10 minutes.

bowen.chau

One more symptom, this only happens when the car has been warmed up.

Does it related to transmission oil filter?

Lexmex

From experience overtime, it takes well over 100 miles of driving after resetting the fuse (roughly 160km) for the vehicle to learn your driving habits and function accordingly. That's the key here.

If the vehicle is in Park and started, it takes about 13 minutes to get up to normal temperature if the vehicle stays parked, and about 3 to 4 minutes if it is put in motion.

bowen.chau

Hi Lexmex, I have drove the car for around 150 km since I have reset the computer. Since, no good sign. Sometimes it is good and sometimes the problem comes out again. Any clue?

Lexmex

What are the bad signs you are getting?

The only other areas that this could be in terms of hesitation are the exhaust (namely a leak around gasket areas), transmission problem (fluid level or the tranny itself has issues (the vehicle turning off at some point is something that stood out to me from your earlier posts), fuel delivery (fuel injectors) or air intake, dirty air intake valve, IACV generally along with MAF causing hesitation.

Would like to know the bad signs of hesitation you are getting.

bowen.chau

Hi Lexmex,

Basically, my transmission acts strange after warming up the vehicle which the author (bchehab) of this post is experiencing. I am experiencing some shift delay from gear 1 to 2 and then gear 2 to 3. Every time when the vehicle shifts gear (both automatic and manual), the transmission does not shift immediately. It will keep in the original gear for 1-2 second before shifting to another gear, i.e. the dash board shows "2" in transmission, but actually the transmission is still at "1", and 1-2 second later, it will shift to "2". However, no hesitation when shifting from gear 3 to 4.

Once, when I have a full stop and shift to "R", the gear does not engaged immediately. It needs 1-2 seconds before the transmission shift gear to "R".

No CEL comes up. No pending code in ECU.
I have pulled the EFI fuse (20A) out for 5 minutes. I have had a "drain and fill" transmission oil changed 2 weeks ago after I have experienced the problem. The fluid level is normal and pink in color.

bowen.chau

I am observing the patterns and it seems that I have found something.

When the hesitation begin, the temperature inside the engine room is relatively high. If I open my hood for a while and then close the hood, the transmission shift normally again.

I noticed that maybe one of my fans (high fans) is not working, i would like to know if a high fan malfunction can cause the hard shifting problem?

bowen.chau

I figured out the problem. It seems like my high fan has stopped working and making the temperature inside the engine room is too high and lead the transmission shift hard.

I have test drove the car with the hood popped up a little for one hour. The transmission shifts flawlessly.
So I will go and change my high fans. Is there any fuse for the high fan so that I can check with?

salimshah

There should be a relay. Either the relay is bad or the signal to activate the relay is not energizing.

Salim

bowen.chau

Hi Salim,

Where is this relay located so that I can give it a change.
The relay should control the temperature inside the engine room, like if it is too hot, it will switch to high fan and noticeable sound should be heard outside the car.
Thank you very much.

Bowen

bowen.chau

I have just checked my two fans behind the radiator. They are both rotating. However, is there any speed control on those fan, like if the engine room is too hot, it will spin faster?

bowen.chau

I have just done another drain and fill today. Disconnected the battery. Still, the jerk and hesitation is still there..

bowen.chau

Guys, any clues?

sfurry

When the O2 sensors are removed my lexus will not shift hard, but when they are hooked back up it shifts very hard in low gear.

The bank 2 and bank 1 were both replaced.

sfurry

My 2000 Lexus RX300 is shifting hard after replacing the O2 sensor when we disconnect it the car shifts fine in low gear, but once we replace the connections it starts to shift hard again in low gear?