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Engine Light Coming On While Towing Caravan-P0046

EddiePato

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Joined
Apr 7, 2017
Messages
3
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australia
Hi,
I had ECU remapping & a new 3" exhaust system put on my 2008 Toyota Prado Diesel in July 2016. In October we went on a 3 week trip with our 2011 Supreme pop top caravan. The Prado was going well & the extra power was worth the upgrade, until the 2nd last day when the engine light came on while under load, going up a steep hill. I drove approx. 10km to our next stop without any problems. When I started the vehicle up in the morning the light was off. When I got home I took it to a mechanic & the fault code was:p0046 : "Turbo/Super Charger Boost Control Solenoid Circuit Range/Performance". My mechanic said it could be a one off thing or it could have something to do with the Solenoid/Stepper Motor on the Turbo. It hadn't come on again until last week when we took off in our caravan again. Coming on, on steep hills under full load. I took it back to my mechanic, who had a used Solenoid/Stepper Motor which he put on, but the engine light still came on towing the caravan up steep hills under full load. The light was off the next day when I started the Prado up. We are starting to think it might be something to do with the ECU remapping. Can anybody help? Regards, EddiePato.
 
Hi Eddie, and welcome to the forum. First let me say I have no experience of your truck. But, I seem to remember another member had a similar fault so it may be worth doing a search on here. Secondly I do know that sometimes remaps can cause issues when under full load with other items like AC on that perhaps weren't run when the remap was done, possibly on a rolling road.

Generic things to check would be connections for correct mating and any corrosion, though I doubt you would find any.

Good luck sorting it.
 
Might a boost leak interfere with electronic management .
 
It may have been the answer on the other thread I'm thinking of Shayne and yes it certainly could so check to see if any things adrift on the intake side and tighten any clamps if needed. Check for splits in intake pipes and hoses.
 
Thanks for your comments. I am probably better off taking it back to the mechanic who did the remapping. Approx. 600km round trip. I have had contact on the phone & he is trying to find out what might be causing it. It appears to be over boosting at the time the light come on.
 
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It will probable be fine if your just sneaking over max boost occasionally when under heavy load, or take it to the mechanic and he'll back things off a little.
 
Boost is digitally managed and you reach max boost every time you accelerate hard but its only at max for a second or 2 until you change gear or you reach the speed you want .

Up hill towing will give you a sustained max boost for far longer giving the computer time to recognize and report a leak .
 
Id put money on the Map needs Backing off a tiny bit. when i first fitted my tuning box, it would bring on the light. turn it off and all is good again. he backed off my maximum setting a couple of times until it stopped doing it.
 
We thought it might have been the variable vane in the solenoid/stepper motor, but replaced it, & it was still doing it. I think you are probably on the right track about the sustained boost while towing the caravan & the Map needing adjusting. Hopefully the mechanic will have some answers for me on Monday. Thanks for your help.
 
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