qewani1

After replacing my car’ s old tires of size 225/60/16 to sizes 235/60/16 in my LS400 2000 model. Since then am experiencing
transmission delay engagement of one-half minute to two minutes after shifting from Park to Drive on MY LS400
By the way no delay when shifting only to Reverse.
The problem is more prevalent in colder weather, and usually
occurs during a ``cold start'' such as after the vehicle has been
parked with the engine off overnight. Normally i increase the engine speed in order to reduce the delay
time.
When transmission fully engaged then i don't have any other problems with it.
I had tried changing the transmission fluid with toyota T-IV ATF + Transmission Oil Stainer, but still having the same
problem. Also am getting CEL on sometimes with DTC P0500 which means Vehicle Speed Sensor Malfunction.
After searching for the relation between VSS and transmission. I found that transmission is controlled by “Vehicle Speed
Sensor” VSS which is located on the automatic transmission. Also I had found that changing to a different tire size than the
original recommend size, may cause problems, especially if the change is excessive and the buffer has not been recalibrated. Check the attached file

Do any one knows about these things? Will replacing the tire size back to 225/60/16 will solve the problem?

PureDrifter

iTrader: (10)

the problem is not related, the size difference between 225/60 and 235/60 is MINUTE, and will not cause the symptoms you are having at all.

qewani1

Are you sure?
Then what about VSS DTC P0500 and what ever mentioned in my previous post in attached pdf?

RA40

iTrader: (6)

Tire size change is minimal. This sounds like a tranny temp sensor issue if it occurs with cold weather. The engine is running fine otherwise? If the VSS is throwing a code, replace the sensor and go from there.

PureDrifter

iTrader: (10)

seeing as how i've run variations as different as 5% (temporarily) and ~2% daily, your difference of all of 12mm in overall diameter is most likely not the culprit.

qewani1

How could i solve the CEL P0500 ? any one got this code before?

qewani1

Does P0500 refer to the speed sensor on tires or the one on transmission?

qewani1

I had attached a PDF which describes how VSS works. Am sure that it’s malfunctioning because of vehicle is being driven with gear in Overdrive + pressing gas pedal, but VSS isn't sending any signal to ECU, so ECU is setting DTC P0500.
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As per this thread where he was having the same issue which am facing currently.
http://www.fordforums.com/f61/tranny-not-shifting-when-cold-169858/

My problem also could be because of a worn vertical shaft where the speed sensor connects to.

Maybe I should start with inspection on the drive shaft.
How could I know if the drive shaft in my vehicle is warned out or not?
Any ideas?