control chip issue?

redsupra · 04-13-2011, 06:14 AM

Hi, hopefully I've found the best Supra resource on the net. There seems to be some very knowledgeable people here.

I'm needing some assistance to solve an ongoing nagging issue with my Supra. It's a MK4 1993 (red, sort of), twin turbo, automatic. I've had this vehicle since Dec 2001 and absolutely love it to bits, despite its foibles as it ages.

I'll describe the main problem and then what I've "discovered" through searches on the net to date. Rememnber this has been an issue for some years and hasn't affected the car to any extent.

O/D light flashes sometime after start (might be immediate, might be after a little while). Front spoiler is inoperable. Cruise control is inoperable.

Now, when this first started I looked up the flashing O/D and one resource said it could indicate a transmission problem. However another indicated something else and the flash rate didn't match the one for the transmission but appeared to highlight a problem with the speed control chip.

Ok. Now, I'm no car techo, I do software, but further research seemed to confirm this. Apparently the front spoiler and the cruise control are governed by this chip and is symptomatic of the general issue (along with the flashing O/D light).

As I understand it this "speed control" chip can have an issue with a loose weld/solder on a contact point and thus the connection and functionality fail (probably indicative of the time that the O/D light starts when sometimes the contact is ok and then breaks and the light flashes).

When this first started, it was very intermitent and I noticed the front spoiler worked intermittently too. I rarely used the cruise control, but tried it a little while back and it does not work any longer (when it used to before all this started).

So, question is: is this analysis correct and how do I go about fixing it? No one (Toyota or my performance car mechanic) seems to know. If I could ascertain the location of this unit and the method to fix it I could probably do it myself (I'm handy with tools, soldering etc). If not myself then get the info to someone who can do it.

Any and all assistance would be greatly appreciated.

Now apart from needing a new paint job, rims, sound system, bushes and possibly some bearings in the fanbelt wheels, all is just fine!

cheers,

Chris

04-13-2011, 06:14 AM	#1
redsupra Stock Join Date: Apr 2011 Location: Melbourne Posts: 8	control chip issue? Hi, hopefully I've found the best Supra resource on the net. There seems to be some very knowledgeable people here. I'm needing some assistance to solve an ongoing nagging issue with my Supra. It's a MK4 1993 (red, sort of), twin turbo, automatic. I've had this vehicle since Dec 2001 and absolutely love it to bits, despite its foibles as it ages. I'll describe the main problem and then what I've "discovered" through searches on the net to date. Rememnber this has been an issue for some years and hasn't affected the car to any extent. O/D light flashes sometime after start (might be immediate, might be after a little while). Front spoiler is inoperable. Cruise control is inoperable. Now, when this first started I looked up the flashing O/D and one resource said it could indicate a transmission problem. However another indicated something else and the flash rate didn't match the one for the transmission but appeared to highlight a problem with the speed control chip. Ok. Now, I'm no car techo, I do software, but further research seemed to confirm this. Apparently the front spoiler and the cruise control are governed by this chip and is symptomatic of the general issue (along with the flashing O/D light). As I understand it this "speed control" chip can have an issue with a loose weld/solder on a contact point and thus the connection and functionality fail (probably indicative of the time that the O/D light starts when sometimes the contact is ok and then breaks and the light flashes). When this first started, it was very intermitent and I noticed the front spoiler worked intermittently too. I rarely used the cruise control, but tried it a little while back and it does not work any longer (when it used to before all this started). So, question is: is this analysis correct and how do I go about fixing it? No one (Toyota or my performance car mechanic) seems to know. If I could ascertain the location of this unit and the method to fix it I could probably do it myself (I'm handy with tools, soldering etc). If not myself then get the info to someone who can do it. Any and all assistance would be greatly appreciated. Now apart from needing a new paint job, rims, sound system, bushes and possibly some bearings in the fanbelt wheels, all is just fine! cheers, Chris