Echo OverDrive Issue

[arthursleep]

Gday

We have a 2003 Echo that has an issue with overdrive.

Basically it won't shift into overdrive. On occasion I can get it to shift into overdrive if I can get it to a decent speed 70+ seconds before the blue tempature light turns out.
This has to be timed right. Once the light is out there is no shifting into overdrive regardless of speed. When it does go into overdrive it's just for that one time, once it drops back into 3rd that's the end of it.

I originally though this might be a temperature issue and thought once the thermostat was opening the engine was running too cool, but the thermo fan still cuts in and out as if it was getting to temperature.

It's been to several mechanics and apparently it's throwing no codes so no issue can be found.

Can anyone help me out?

Cheers
Arthur

[ex-x-fire]

You need to measure the temp while going down the road.
At low speed/idling there is little air flow to cool the coolant, so the temp will increase till the fan turns on. Going down the road you have a lot of air blowing through the radiator, keeping the temps way down.
Do you have a temp gauge? Is it reading low? What's the temp down there? Its winter season right?

[arthursleep]

The fan cycles whilst moving, not just idling.
It's coming into winter so it's getting pretty cool at the moment 28°-59°F, but this issue was present during summer 60°-104°F.
The car doesn't have a temp gauge, just the blue and red lights.

[IllusionX]

Gday

We have a 2003 Echo that has an issue with overdrive.

Basically it won't shift into overdrive. On occasion I can get it to shift into overdrive if I can get it to a decent speed 70+ seconds before the blue tempature light turns out.
This has to be timed right. Once the light is out there is no shifting into overdrive regardless of speed. When it does go into overdrive it's just for that one time, once it drops back into 3rd that's the end of it.

I originally though this might be a temperature issue and thought once the thermostat was opening the engine was running too cool, but the thermo fan still cuts in and out as if it was getting to temperature.

It's been to several mechanics and apparently it's throwing no codes so no issue can be found.

Can anyone help me out?

Cheers
Arthur
This is standard behavior for the automatic transmission to help warm up the car before the blue cold light goes out.

[arthursleep]

This is standard behavior for the automatic transmission to help warm up the car before the blue cold light goes out.

I completely understand that.
But I still have no overdrive once the blue light goes out.

[IllusionX]

I miss read your first post.

Need CTScott to report in. Lol

[arthursleep]

Is CTScott the overdrive expert? I've seen his bypass, which is an option if this problem can't be fixed.

[arthursleep]

Ok, so I can't find much if any information on my issues the process of elimination will proceed.
I know overdrive works, so I'm going to concentrate on the engine side of things first.

Does anyone know which of the two temp sensors is for the auto?

[Lux]

Having a technician scan for DTCs is meaningless because your automatic transaxle control module is not capable of self-diagnosing overdrive functionality.
No DTCs ≠ no diagnosis.
If the conditions are met, the ECU commands the upshift. You need to verify those input conditions: vehicle speed, engine speed, throttle position, water temperature, overdrive switch, etc.
You can see most of that in 5 minutes with a half-decent OBD-II diagnostic scan tool that supports live data.
If it all checks out, you can start checking line hydraulic pressure to the overdrive solenoid, overdrive brake condition (any friction material left when commanded on?), whether it's seized or unable to overcome overdrive hub spring tension due to failing accumulator, etc.
This driveline failure might be out of your scope given the complexity of automatic transmissions. I would suggest taking it to a transmission specialist.

By the way, this is what your transaxle roughly looks like inside
http://i60.tinypic.com/2881quv.jpg

[arthursleep]

Thanks buddy, but the overdrive actually works.
But, something is stopping it from shifting into overdrive.

[shepd]

I don't know the wiring, but if the ECU is controlling the transmission then one possible failure that could be looked at without a scanner and found without significant experience would be to check if the signal to shift to overdrive actually makes it to the transmission. Perhaps a wire is damaged?

[arthursleep]

It's possible.
I'm still going to try the sender first, I went to Toyota early last month but they were out of stock.

[CTScott]

The most common reason for it not to is the transmission temperature sensor being bad. The ECU uses it and the engine temp sensor to determine when it is OK to allow the tranny to shift into overdrive.

[woops]

^yep its probably either the transmission temp or engine temp sensor

[arthursleep]

The most common reason for it not to is the transmission temperature sensor being bad. The ECU uses it and the engine temp sensor to determine when it is OK to allow the tranny to shift into overdrive.

^yep its probably either the transmission temp or engine temp sensor

Thanks guys, I was going to start with the engine temperature sensor, but might as well do them both to save a trip to toyota.

Is the transmission temperature sensor accessible from the out of the transmission?
Got a pic of it's location?
Cheers

[CTScott]

Thanks guys, I was going to start with the engine temperature sensor, but might as well do them both to save a trip to toyota.

Is the transmission temperature sensor accessible from the out of the transmission?
Got a pic of it's location?
Cheers

The temp sensor is located on top of the tranny, and is accessible with the battery and intake box removed.