The Mitsubishi Pajero Owners Club®

Ash2.8 · Posted: Tue Jun 13, 2017 17:20 Post subject:

Update.

Just fitted the throttle position sensor from a breakers yard off a working truck... no change, still gets stuck in top gear.

I have a few questions for you....

1) As you slow down, what tells the gearbox to change down a gear? ie as you drop from say 50mph to 15mph, what tells the gearbox to change down? Is it the speedo, then the ecu to the gearbox?
2) What is the job of the throttle position sensor. The pump has a kick down cable on it, so what does the TPS even do?

It appears that when you drive the truck up the road when stone cold in the morning, overdrive works. The gearbox changes up into top gear. revs are around 2600rpm at approx 60mph, then i select overdrive and revs dropto 1900rpm ish.
Then as i continue and truck warms, it appears that it jumps out of overdrive and back into 3rd, where it now revs again at 25002600rpm doing 60mph.

At this point, the truck will not change down out of 3rd gear.

When the truck is still warm, i pull into a layby, select park and then back into D and its stuck in 3rd still.
So.... i then re select park, turn the truck off and back on again. Then i selsct D and away it does, changes up 1st, 2nd, 3rd... but this time overdrive does not work.

To conclude, my findings are when cold overdrive works. When warm, it does not.
Once the truck gets into 3rd, it will not change out of 3rd.
Unless of course driving it manually.

I disconnected the 2 prong temperature sensor on the top of the cylinder head (just under the interccoler), that gives a signal to the temp gauge on th dash, this had no change on things either.

Slowly running out of options now.

Any help? Cheers

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peteinchad · Posted: Tue Jun 13, 2017 18:04 Post subject:

I would change the gearbox ECU - they are quite cheap on eBay and easy to get at to change. At least it would rule it out.

Ash2.8 · Posted: Tue Jun 13, 2017 19:42 Post subject:

Ok thanks. Do you have any answers to my 2 questions?

Cheers

peteinchad · Posted: Tue Jun 13, 2017 19:57 Post subject:

peteinchad · Posted: Tue Jun 13, 2017 20:01 Post subject:

ECUs on eBay seem to vary widely in price - the one with the same part number as my truck is about £20.

At that price it is worth changing it to rule it out as the source of your problem - if it makes no difference you can always stick it back on eBay.

Ash2.8 · Posted: Tue Jun 13, 2017 20:20 Post subject:

Just been having a look on ebay. They do vary in price and some are untested so it is a gamble.

Would an ecu cause it to stick in a top gear?

Im just scratching my head... what gets me is that the gearbox goes back into bottom gear after switching it off again.
So turning it off temporarily fixes it until it develops the same problem again lol

Also just tested continuity from the single spade coolant sensor on the head to the ecu plug and there is continuity.

Cheers

peteinchad · Posted: Tue Jun 13, 2017 20:33 Post subject:

Ash2.8 · Posted: Tue Jun 13, 2017 20:56 Post subject:

Thanks again for the help.

Will keep you all updated.

Cheers

kenthepipe · Posted: Thu Jun 15, 2017 18:42 Post subject:

Here's a bit info re the TPS..,

http://www.pocuk.com/forums/viewtopic.php?t=70087&highlight=

Steve_C · Posted: Fri Jun 16, 2017 13:40 Post subject:

When you say "stuck in 3rd", I assume you mean that you have 1st, 2nd and 3rd, but not top gear?

I had exactly this on my Sport, and it turned out to be a dodgy switch on the transfer box which was telling the ECU that low range was engaged, even though it wasn't. If the ECU thinks low range is selected, it won't allow top gear to be selected.

eve.st · Posted: Tue Jun 20, 2017 21:37 Post subject:

i tested a2.5 auto drove slow and noisey would not kick down ,but could use it manually i asked a few Qs from a few guys that run japs and they suggest selecter switch ormode switch ecu g/box connection or--diesel pump connection apperantly istsends and recieves from ecusounds odd but ithought i,d thtow it in

dhammika · Posted: Fri Jun 23, 2017 7:58 Post subject:

It seems like after some time, your two main shift solenoids are not functioning either due to loss of electrical signal or failure in solenoids.

Pajero V4AW3 Transmission is built by Aisin-warner and their model name is AW30-40, which is similar to 4x4 AW4 and Toyota A340E series

Looking at the literature, when both the solenoids are not functioning, gearbox selects the default gear based on the shifter position. When the shifter at "D" position, default gear is O/D.

https://drive.google.com/open?id=0BzJBT050_Ju3TUpIT1RVN0Zaa3c

So as Pete suggests, first check replacing the ECU

BILLYWHI33 · Posted: Tue Feb 20, 2018 14:45 Post subject:

Hi mate i had the same problem on my 2.8 swb tried allsorts even gearbox ecu still no joy i ended up changing the gearbox. That worked!