96' Hiace

Auto Trans wants to shift into high gear while taking off from stop.....? Going to try fluid change. Guess it could be ECU brain going haywire, HELP! Thanks

I think it may be a default position if one of the transmission solenoids is failing. I'll see if I can find the details in the repair manual.

Is it a diesel or petrol Hiace?

Hi - hopefully, it's an electric controlled transmission - it may say something like A45DE (e is electronic). It'll be printed on a plate on the side of the transmission - and also on the chassis plate by the engine bay.

If you go to the Hiace South East site and open the RZH-LH manual, open Repair Manual -> Diagnostics -> Automatic Transmission A45DE.

Go through the diagnostics pages in order, but if it's the solenoids, or it's wiring, it looks like solenoid 1 - see the 62/63 file. Page DI-27 show the symptoms when one of the solenoids fail - the symptoms are that it will only use 3rd and O/D - unless you shift it to 'L' - in which case it will only use 1st and 2nd.




But check for DTC codes first - usually the check engine light will stay on to indicate that there's an issue, but I've have it where the light isn't on, but checking for codes will indicate an issue. If you have an electronic controlled transmission, it can send codes back to the ECU. The instructions are somewhere within the manual pages, but there's lots of videos - like this one: https://www.youtube.com/watch?v=eJqYCVXudys

If you get code 62, then that will confirm it's the 1st solenoid.

I think, if there's a transmission issue, the O/D Off light may flash too.

Its a Diesel A340F Auto. I change the filter, fluid, and checked the 1 and 2 sensors They would click when hooked up to 12V. Sometime Its doesn't want to shift into 1st gear coming to a stop or want to shift into drive, taking off from a stop.So First and Second gears...Guess I need to check ECT and ECU, not sure if ECT is even available. ECU can be recapped. Thanks I'm at a lost state. 96' Hiace KZH 106 Sometimes it works perfect threw all gears.Look like Amayama has them at $400 something. Looks like its somewhere below shift lever under dash. Just not sure that is the problem.   Thanks G00se

I had an ECT issue on my petrol hiace. the transmissions on the petrol ones are not electronically controlled - unlike yours - apart from the overdrive solenoid. Occasionally, it would just drop out of O/D for a few seconds for no reason - but only after it had been sitting in traffic for while and then hit motorway speeds. I thought it was the transmission getting old - had it checked and the fluids changed - but it turned out to be the ECT - the temp sender the ECU uses. £20 for a new one and it was fixed. The ECU is designed to block the use of O/D when the engine is cold - the temp sender would occasionally drop to 'freezing' and cut off the O/D.

I only worked it out after the van would not start when trying to start from hot. The temp sender was telling the ECU the engine was cold and it would flood the hot engine. I thought it was injector issues but only worked out the sender was the problem after using a scanner on the OBD1 port - I could see the ECU reporting the temp was cold.

It might me worth seeing if you can get hold of a OBD1 reader? A Toyota garage may have one - or you could see if you could get hold of a TOYOBD1 device - there's a guy on Facebook that makes them. A bit like hen's teeth - but occasionally folks sell them used. It may help identify any transient ECU issues.

One thing to try - and it was what confirmed it was the temp sender for me - was to unplug it. With it disconnected, the ECU assumes the engine is at 80 deg C. It might be worth a go.

This may help - https://www.youtube.com/watch?v=6sSzBUh1XwA&t=571s

It's a shame where it is, on the petrol engine, it's easy to get to from the top. I'd suggest just unplugging it for a while and see how it behaves. it may be a little lean when it's cold though, but the ECU will assume it's at running temp (80C). If you do end up replacing it, do it when the engine is stone cold - you'll loose less coolant as it won't be under pressure.

Another thing the guy says is that the A340F control comes from three sensors - temp, speed and throttle position. It'll be worth going through those in order to see if they are the cause.

Ha,Ha. I realized that trans didn't act up till I had throttle body off, while changing Glow plugs....went out and checked kick down cable and it was loose. Tighten and went for a thirty mile drive and WORKS GREAT! Thanks, so much for the help. g00se. So helpful....

That’s cool! It’s great when a you get to solve an intermittent issue like that.

Guess I spoke too soon, trans works great for the most part.
Starts to act up running around town for a few miles, then starts to work again....perplexed, Put a new battery in and heard the I guess ECU computer fire up under dash by shifter. Just need to find someone who can diagnose, near small town.

Refurbished ECU took care of everything. Thanks for all the Help.