A transmission fault code that's not on the list...

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sema4
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A transmission fault code that's not on the list...

Post by sema4 » Thu Mar 25, 2021 7:37 pm

Hello all

This is my first post since getting the bongo ('96 RWD 2.5D Auto) - and I just wanted to start by saying a huge thank you to everyone on here for the wealth of information and help that you have posted.

I got my membership straight away, and that's been brilliant with the fact sheets too.

So, first things first - our bongo has spent most of it's time at the garage already (Japtech in Southampton as recommended by the members). It's had it's turbo reconditioned, part of the exhaust replaced, part of the underbody coolant distribution replaced and a reconditioned fuel pump. It's now running OK - but I have the HOLD light flashing. The HOLD light has only been on since it's last visit to the garage to have the fuel pump sorted because it was leaking diesel. So I followed the procedure to read the diagnostic codes and I get:

12 - Throttle Position Sensor
36 - ??

So 12 makes sense - and I was kind of expecting that - seeing as the TPS is attached to the fuel pump. So I'm going to have a go at the contacts for the TPS connector with some contact cleaner and apply a little grease to the outside of the connector to make sure it mates properly. But 36 is a bit of a weird one - I can't find it in any of the transmission fault code lists anywhere. I do have the bongo booked in with AutoTune in Hedge End (who apparently have a fault code reader for the diagnostics port), so I will post back here if I find out what 36 actually means.

But - my question to you guys (and, hopefully, alacrity!) is - what sorts of things should I be checking other than electric plug contacts? Also - I have seen the schematic around the transmission electrical system - but one thing I haven't seen is a physical description of where those connections actually end up... is there such a thing? I don't have a lift or anything like that so it's kinda difficult for me to trace things under the body, and the van has a side conversion which means someone has to hold the driver's seat upright if I want to look under there...

Anyway, thanks in advance for any help/insight

Cheers

Matt
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Re: A transmission fault code that's not on the list...

Post by Ian » Thu Mar 25, 2021 8:06 pm

As Mazda use the same fault codes throughout their models it's possible that code 36 is a problem with the Oxygen Sensor. Have a look at this:

https://www.troublecodes.net/mazda/

BUT yours is a diesel, so I wonder if it,s a problem with the air intake sensor? AutoTune should be able to tell you.
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sema4
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Re: A transmission fault code that's not on the list...

Post by sema4 » Thu Mar 25, 2021 8:38 pm

Thanks

Would air intake / oxygen sensors get reported through the transmission fault codes?

One thing I don't really understand is whether shorting the pins on the diagnostic connector shown in the transmission code fact sheet just reads codes related to the transmission - or whether it reads all codes and just happens to make the HOLD light flash.
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Re: A transmission fault code that's not on the list...

Post by mikeonb4c » Fri Mar 26, 2021 10:16 am

Out of interest, is the Bongo driving normally, gears changing ok. What does the HOLD light do if you press it while driving (and do engine revs change etc).
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Re: A transmission fault code that's not on the list...

Post by rita » Fri Mar 26, 2021 2:23 pm

Contact or Take it back to the garage that carried out the work to the FIP , it could be a TPS fault.
sema4
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Re: A transmission fault code that's not on the list...

Post by sema4 » Sat Mar 27, 2021 3:05 am

It does seem to be driving OK - but we have deliberately kept it at low speeds because of the issue. Also, it has to be said that we don't really have a good baseline for 'driving normally' as it has spent most of it's life with us at the garage. I haven't tried the hold button though...

But I will be doing some work inside the van (tidying up the conversion wiring and wiring up the heated seats) so when the contact cleaner comes I will give that a go and see what happens.

Looking at the fuel pump, the TPS is marked up so it looks like they did calibration... I will post again when I know more...
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Re: A transmission fault code that's not on the list...

Post by sema4 » Sat Mar 27, 2021 6:21 pm

Ok - so contact cleaner didn't help. The gear shift from 1->2 is a bit jerky, and kickdown isn't doing anything other than accelerating. The hold button isn't doing anything either. I don't know whether kickdown/hold aren't working because there's a transmission fault code - I don't really know what the transmission would want to do in that mode... So yeah - I'll see what happens with AutoTune on Tuesday and when I know what those fault codes mean, then I will take it back to JapTech.

Thanks for all the help so far
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Re: A transmission fault code that's not on the list...

Post by sema4 » Fri Apr 02, 2021 4:06 pm

So, update...

The HOLD light would flash immediately when the ignition was turned on - I adjusted the TPS a little, and now the light only starts flashing when you accelerate hard...

So I think I just need to adjust the throttle position sensor.

My question is - is there anywhere that has a guide on how to do this? There's a bunch of threads on here referring to the Bongo Wiring Manuals - but they are now dead because Flash got deprecated. There's some others showing the right pin on the ECU in a picture... that's now broken :) And the search doesn't like three letter terms - so ECU and TPS are right out...

I really just need to know where I need to attach the multimeter in order to calibrate the TPS correctly and then I am golden (I think). I know that with the ignition on, I need to adjust is so that the voltage at the ECU is 1.3v closed, 4.2v open with reference to the vehicle ground.

Can anyone help me identify which pin on the ECU I should be testing?

Thanks!
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Re: A transmission fault code that's not on the list...

Post by g8dhe » Fri Apr 02, 2021 4:59 pm

The wiring diagrams won't help you there you need to adjust the TPS for the correct voltages on the ECU as in the engine manual.
See here viewtopic.php?p=566167#p566167
Its the Orange/White wire on the 2I connector
dieselTPS.jpg
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Re: A transmission fault code that's not on the list...

Post by mikeonb4c » Sat Apr 03, 2021 8:58 am

Only just seen the latest posts as forum software didnt flag them up as new. Sounds encouragingly like it may just be TPS related. Hopefully (esp with Geoff on hand to direct you to data) the problem will get tracked down and sorted. Good luck and keep us posted.
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