Automatic gearbox fault

Technical questions and answers about the Mazda Bongo

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SteveG
Junior Bongonaut
Posts: 24
Joined: Fri May 01, 2020 8:32 am
Location: Essex

Re: Automatic gearbox fault

Post by SteveG » Thu Aug 20, 2020 7:31 pm

Needed the crank sensor to get the rev counter working again. Will then review the performance of the auto box. May still need the solenoid pack. The gearbox makes no noise, changes through the gears well and pulls me uphill with no problems whatsoever.
Happy to hear what you have to say.
Many thanks!
SteveG
Junior Bongonaut
Posts: 24
Joined: Fri May 01, 2020 8:32 am
Location: Essex

Re: Automatic gearbox fault

Post by SteveG » Mon Oct 05, 2020 3:06 pm

Update on the gearbox fault.
ATF changed and filter cleaned.
Crank sensor changed.
Solenoid pack changed.
Fault still present!
Took it to Martin at DRA Services Croydon who without looking diagnosed a faulty throttle position sensor (on the diesel pump). I had recently replaced the pump which in its recon/exchange form comes with the TPS. Mine was faulty. Problem solved.

So. Can somebody explain why the TPS should have anything to do with auto gearbox faults????

Cheers
Steve
User avatar
g8dhe
Supreme Being
Posts: 8791
Joined: Sun Apr 13, 2008 10:06 pm
Location: Worthing, West Sussex.

Re: Automatic gearbox fault

Post by g8dhe » Mon Oct 05, 2020 3:10 pm

The TPS tells the ECU the engine throttle setting, i.e. how much power is being generated, this along with the road speed and engine speed tells the Transmission Control Module how to set the gearbox up for the appropriate gear - wrong TPS setting and the wrong gear settings are setup.
Geoff
97 V6, AFT, full side conversion.
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