CEL light, no codes, comes back after downshifting???

[aaron7]

Ok. Full story.

96 Avalon V6. Had a torn CV boot. Had the shop replace the axle. As we all know, the axle seals are VERY touchy. They bumped one. Didn't realize it. Drove the car for a day; all fluid leaked out... tranny smoked.

Shop installs a junkyard tranny. Unknown shape, miles, or year.

Car drives fine. Shifts fine. But CEL light has been on since.

I've checked for codes, I've had AutoZone check for codes, and I had the dealer check for codes. None.

If you reset the light it stays off till you drive the car and it downshifts. The light also will come on if you turn the car off and back on.

The car cannot pass MA inspection with the CEL light on; even if there are no codes. Deadline is coming up fast before the car has to be removed from the road.

The shop that put the tranny in has "exhausted their testing" and "will not help further".

Please keep this technical and not "go sue them" or whatever. That might eb the case but it doesn't help right now.

[toyomoho]

Can you read out any trans codes by:

Ign switch and O/D switches on

Short the Tt and E1 terminals in the small diagnostic box in the engine compartment.

If a code(s) is stored the O/D light will flash them out one numeral out at a time. If no codes the light will just flash at a steady rate.

The trans has its own computer. Could the shop have screwed up the wiring, perhaps engine wiring?

Strange the Toyota dealer can not come up with anything.

[aaron7]

Well, after months of diagnosis and different shops, one shop found the problem.

There was a tranny connection on the back that was only visible on a lift. Guy pulled it and the connection was all corroded.

Cleaned it up and BAM... CEL out and transmission shifts nice and smooth.

To think we tore the dash out and replaced the ECU... AHHHHHHHHHHHHHH

[toyomoho]

Great!

Thanks for posting back with the fix.