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Discussion Starter · #1 ·
To my fellow spyderchat mates,

I wonder if someone here can advise me.

Background:
I purchased this beautiful 03 MR2S-SMT in January (60k miles and the prev owner treated it well). Had been sitting for 3 months before I purchased it (she had bought a new car).

DESCRIPTION OF FLAKINESS
If I drive for more than about 20 miles, the following SMT flakiness occurs every time. While driving away from a stop, and rowing through the gears, the transmission disengages by itself, and I can't make it go back into gear, and I've no choice but to roll to a stop (pull over to the side if I'm lucky). Two idiot lights glow: a) check engine, and b) the red, gear shaped symbol. I can get the car to behave normally again by turning it off, removing the key, and then going through the start up process again.

However, for a given trip, once the SMT flakiness has occurred, it keeps reoccurring, and for every occurrence I'm forced to roll to a stop, turn off the car, remove the key, and go through the starting up sequence again. This goes on until I get it home and park it in the driveway.

Funny thing is that after about a week (I only drive it about once a week), when I go through the start up process again, the car behaves normally. And both idiot lights are no longer lit. And it appears to behave perfectly normal, once again. That is until I've driven it again for about 20 miles. Then the exact same SMT flakiness, described above, occurs again.

This has happened to me every time I've driven it more than about 20 miles, which means that this has happened to me about 10 times over the last four months.

WHAT I'VE TRIED
Back in January, after the first occurrence, I became a spyderchat member and researched SMT issues. Although I didn't find a perfect description of my car's problem, I did learn that taking it to a Toyota dealer can be an expensive, and wasteful proposition. Also, back then since the issue had only occurred twice, and fixed itself both times, I thought maybe it would permanently fix itself over time; that maybe it was only acting strange because it had sat for several months before I purchased it. (BTW, after doing research, on this site, at that time, I purchased and installed a new battery, which doesn't seem to have mitigated the flakiness one iota).

ERROR CODES
The problem just occurred again today, and while the check engine idiot lite was still on, I brought it to a shop and obtained the computer codes. There are two codes:
"P0860" ... gearshift code
"P1646" ... computer code

Can anyone help me diagnose the problem? I hate the thought of bringing it to a dealer that may not know how to diagnose it properly.

Thanks much,
Mark
 

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After reading your Story of SMT Driving Challenges, I sat down with my Morning Tea, and a Copy of the SMT BGB for the '03.. It's not a lite read, but passes the Time while the Tea takes effect..

No 860 Listed in the Book.. Hmmm This day is a Little More complicated already..

I Searched the SMT Forums and found this.. Where this really Smart gentleman could also not find an 860 Code..
http://spyderchat.com/forums/showth...6-any-ideas-what-the-problem-is&highlight=860

Please re-read the Code and Post your Findings.. see if there also might be more codes..

Cap
 

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Did this start before or after you spilled the coke? .p0860 is gear shift module code, more precisely it what happens when 2 conflicting messages are given of what you want to do (up and down at the same time, neutral and S, S and reverse, etc) , clean the contacts at the base of the shift lever, and make sure your steering wheel buttons aren't sticky.
 

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The Code of P0820 refers to the Gear Lever X-Y Position Sensor Circuit.

That is the Thing in the Cab, that you spill the Coke on..

Page DI-284 on the '03 MR2 Book Volume 1

Cap
 

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The Code of P0820 refers to the Gear Lever X-Y Position Sensor Circuit.

That is the Thing in the Cab, that you spill the Coke on..

Page DI-284 on the '03 MR2 Book Volume 1

Cap
Yup, but that's if only the one on the console is messing up. If the steering wheel and the console conflict it throws the p0860, that's one of the few codes you can force it to throw while in the drivers seat. If he uses the steering wheel to shift and the console is stuck or if he uses the console to shift and the steering wheel is stuck, that's what he would get.
 

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Discussion Starter · #8 ·
My 1st hunch is that this flaky behavior is temperature related, since the problem doesn't occur until its been driven for a while, and because it clears itself (transmission functions perfectly again) after it has sat for a while (haven't yet measured how long it has to sit before problem clears).

2nd hunch is that SMT fluid level may be low (thinking here is that while driving, fluid gradually becomes more dispersed throughout the system. If not enough fluid then pressure gradually becomes too low. Parking car causes fluid to gradually be centrally collected, allowing pressure to remain within reqd limits until car is again driven for a while).

I like Plebian's theory, but have these questions:

a.1) I can and will, if necessary, try to obtain the third fault code, as suggested by a previous post. However, it seems that Plebian is suggesting that the P0860 code conclusivelt narrows the flakiness down to the driver shifting switches. Do I still need to obtain the third code?
a) Once car is in motion, I pretty much always use the steering wheel buttons, and I think that's probably how I was shifting during all of these instances of flakiness.
b) Why would the button switches, or the stick switches for that matter, behave abnormally only after the car's been driven for a while?
c) other posts have suggest that the problem may be one of the GSU position sensors. I wonder how this could explain the flakiness I'm seeing.
d) I remember reading a few months ago, not on this site, about a women who's MR2S's SMT was behaving similarly to mine. After typical dealer waste of time/money, out of desperation her non-Toyota mechanic tried disconnecting the steering wheel shift buttons completely, and this ended up completely fixing her problem (except now she could only use the stick for shifting).
e) Does anyone know how to clean/replace the steering wheel switches? The stick switches?
f) Even if the flakiness turns out not to be SMT-fluid related, after 60k miles is it advisable to replace that fluid anyway? Not considering cost, is the Toyota SMT fluid the best stuff to use?
g) When replacing the transmission fluid (as opposed to SMT fluid), is it best to purchase from dealer, use Redline MT-90, or some other option?

Thanks all!
Mark
 

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So far this has been very informative.

From previous posts, the Wires in the Steering wheel Column, can break.. and cause the Button or the Cruse Control not to work..

From what I remember of the Steering wheel Button, they are Make Only.. so the Break in the Wires SHOULD not cause any Issues, other than Non Function.. I've been Wrong Before.. ( I can Give you My Ex-Wives phone number if you'd like some proof )..

Check the SMT Fluid under the Air Box, and yes New Fluid is always a Plus.. Changing is good.. unless you are a Complete Idiot, and let a bunch of Dirt in at the Same time.. then Changing it was not such a great Idea.. Use your best judgment on that Subject..

Then take the Car for a drive and ONLY use the Center Shifter.. see how it goes..

Good Luck..

Cap
 

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So far this has been very informative.

From previous posts, the Wires in the Steering wheel Column, can break.. and cause the Button or the Cruse Control not to work..

From what I remember of the Steering wheel Button, they are Make Only.. so the Break in the Wires SHOULD not cause any Issues, other than Non Function.. I've been Wrong Before.. ( I can Give you My Ex-Wives phone number if you'd like some proof )..

Check the SMT Fluid under the Air Box, and yes New Fluid is always a Plus.. Changing is good.. unless you are a Complete Idiot, and let a bunch of Dirt in at the Same time.. then Changing it was not such a great Idea.. Use your best judgment on that Subject..

Then take the Car for a drive and ONLY use the Center Shifter.. see how it goes..

Good Luck..

Cap
I haven't looked at the wire itself to see if it's just a positive wire or a positive and negative wire which can pinch and short out.

As to reason why it would only happen after awhile, might just be how the odds are working out. If it happens in 1 out of 1000 button pushes, the chance of it happening increases the longer you drive.

Of course it might not be the cause of the problem, just may be an effect of the driver going into panic mode and just hitting everything to make it do something. If you actively push the lever and the buttons at the same time in opposite positions it will throw the code. Really curious as to what the 3rd code is, it may be the cause of the problems and the other 2 may just be symptoms of the driver trying to do something and the car refusing.
 

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Discussion Starter · #11 ·
Tried to induce P0860 code

Plebian,

I liked your theory about the 860 code and thought I'd try to induce one by entering conflicting command from the buttons and the stick. I was hoping that I'd be able to induce the same flaky behavior that I see after driving for about 20 miles.

Yesterday I tried to trigger the 860 code but simultaneously pressing the steering wheel buttons, and activating the stick. I tried this about 20 times, for multiple combinations of speed, initial gear setting, etc.

For example, while traveling at 25mph in second gear, I used a button to shift down while using the stick to shift up, and vice versa. Also tried simultaneous shifting up and simultaneous shifting down. Wasn't able to get the car to misbehave or get the SMT light to turn on.

The car was barely warmed up (i.e. I hadn't driven it for enough miles for it to start acting "flaky" yet).

Do you know of a better technique that I can use to trigger an 860?

Next I'm going to drive it around until the SMT light turns on (about 20 miles), and bring it to a shop so that I can get the 3rd code.

I'm also going to inspect the SMT fluid and add a little, if necessary.

Thanks for any help you can provide.
Mark
 

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Does not have to be a 3rd code..

The Codes are stored in Memory.. and are not cleared automatically.. so if it tripped a code, it's still there..

Cap
 

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Plebian,

I liked your theory about the 860 code and thought I'd try to induce one by entering conflicting command from the buttons and the stick. I was hoping that I'd be able to induce the same flaky behavior that I see after driving for about 20 miles.

Yesterday I tried to trigger the 860 code but simultaneously pressing the steering wheel buttons, and activating the stick. I tried this about 20 times, for multiple combinations of speed, initial gear setting, etc.

For example, while traveling at 25mph in second gear, I used a button to shift down while using the stick to shift up, and vice versa. Also tried simultaneous shifting up and simultaneous shifting down. Wasn't able to get the car to misbehave or get the SMT light to turn on.

The car was barely warmed up (i.e. I hadn't driven it for enough miles for it to start acting "flaky" yet).

Do you know of a better technique that I can use to trigger an 860?

Next I'm going to drive it around until the SMT light turns on (about 20 miles), and bring it to a shop so that I can get the 3rd code.

I'm also going to inspect the SMT fluid and add a little, if necessary.

Thanks for any help you can provide.
Mark
I liked Plebian's theory as well but I couldn't induce the code either. What was the outcome here?
 
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