Hilux limp mode issue

Submitted: Tuesday, Nov 07, 2017 at 17:03
ThreadID: 135839 Views:8392 Replies:7 FollowUps:15
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Hi folks, hope someone can help with my problem.
My 2006 D4D lux slips into limp mode under light throttle on a rough track or corrugations.
Had a similar problem 40K or so ago when it tripped out under load but had a diesel mechanic clean the gummed-up EGR valve and inlet manifold and plug an inlet vacuum leak.
I find it hard to believe things have gummed up again so soon and I've had no issues when under load.
Currently in Esperence and will be in Perth in a week or two and look for a diesel mechanic with a diagnostic tool to check the system's memory.......any suggestions?
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Reply By: Legendts - Tuesday, Nov 07, 2017 at 18:46

Tuesday, Nov 07, 2017 at 18:46
Shep, do you have a Scangauge? If not it will allow you to clear the fault code/s. I know that’s no real help for your problem but does keep you on the road if out bush.

AnswerID: 614835

Follow Up By: IvanTheTerrible - Tuesday, Nov 07, 2017 at 19:43

Tuesday, Nov 07, 2017 at 19:43
You do know that if there is a fault the nothing short of fixing it will clear the code? Scangauge will also only give you the code. It is up to the user to have a list of what the codes mean.
FollowupID: 885528

Follow Up By: Legendts - Thursday, Nov 09, 2017 at 22:04

Thursday, Nov 09, 2017 at 22:04
That’s stating the obvious or so I thought.
FollowupID: 885578

Follow Up By: Gramps - Thursday, Nov 09, 2017 at 22:12

Thursday, Nov 09, 2017 at 22:12
Once you've got the code try this

FollowupID: 885579

Reply By: RMD - Tuesday, Nov 07, 2017 at 18:58

Tuesday, Nov 07, 2017 at 18:58
Has it been used much of it’s life at light throttle? If so either the throttle position sensor or the throttle pedal unit maybe worn in that area and causing an ECU error.
If on rough roads it could be a loose earthing terminal which is not connecting sometimes and the ECU sees it as a fault when it occurs.

The vehicle won’t have a vacuum leak on the manifold because it is always pressure in the manifold. It is a turbo vehicle.
AnswerID: 614836

Follow Up By: Shepbar - Tuesday, Nov 07, 2017 at 20:03

Tuesday, Nov 07, 2017 at 20:03
Thanks for those suggestions RMD. I had already checked the earth at the battery terminal, but maybe there's another lose connection somewhere.
Yes lots of cruising on light throttle over the years as it has a diesel-gas system installed. And before you suggest this may be the problem, I have the same problem with the gas turned off and running straight diesel.
I'll pass on your comments to a diesel mechanic when I find one in Perth.
Any recommendations for a mechanic by you Perthies out there?
FollowupID: 885531

Follow Up By: RMD - Tuesday, Nov 07, 2017 at 23:01

Tuesday, Nov 07, 2017 at 23:01
I didn't mean the battery terminal, it is the most unlikely to be the problem as it passes enough current to start. It is likely to be a body earth which has been bolted to the cabin sheetmetal, either inside or outside the cab and is an earth for the systems. There are a few of them, some singles and some multiple eyes which could be firmly bolted to a nice paint underside and vibes make it not touch sometimes.
I know of Nissan Navaras which has similar problems and until it was accidently found by removing the bolt and cleaning to make a good contact, when it happened the vehicle just stopped dead. No start. All the injectors earth to negative somewhere and their connection to negative has to be good. If done through the ECU it's neg connection must also be correct.
Look for any wiring to earth/negative and check the integrity of the connection. If you find a loose one then rattling will make it intermittent.
Such a fault may show a code but not indicate where or what.
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Follow Up By: Shepbar - Wednesday, Nov 08, 2017 at 09:34

Wednesday, Nov 08, 2017 at 09:34
Sounds like I need to find someone to devote some serious time to exploring all these connections both under the bonnet and from under a hoist.
Thanks again for your thoughts RMD.
FollowupID: 885539

Reply By: Member - William B (The Shire) - Wednesday, Nov 08, 2017 at 09:25

Wednesday, Nov 08, 2017 at 09:25
Hi Shep,
I had a similar problem where my '07 D4D Prado would do the same sort of thing.
Do you have a tuning chip on it?
Mine has a DP Chip on it. I reset it to a slightly more conservative setting and every thing is working well.
Always planning the next trip. VKS-737 mobile 1619

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AnswerID: 614845

Follow Up By: Shepbar - Thursday, Nov 09, 2017 at 22:51

Thursday, Nov 09, 2017 at 22:51
No chip, but thanks for your sugg William.
FollowupID: 885580

Reply By: Dean K3 - Wednesday, Nov 08, 2017 at 14:39

Wednesday, Nov 08, 2017 at 14:39
throttle position sensor be my top suggestion

sounds like a intermittent issue, so unless a diagnostic tool was fitted and managed to capture the error code when it occurred it maybe hard to diagnosis properly

i doubt its a mine spec witha sneaky speed limiter fitted, drove one with max of 60kmph that was damn difficult in peak hour traffic

I could never fault city toyota, but have heard a few issues with other dealerships around the place.

Suggest TLC down O'connor -however they usually have a waiting period before servicing spot is available.
AnswerID: 614850

Reply By: pop2jocem - Wednesday, Nov 08, 2017 at 15:06

Wednesday, Nov 08, 2017 at 15:06
If I am understanding some of the replies I find it hard to see how with the advances in the engine/transmission management systems fitted to more recent versions don't include current and historic storage of fault codes.
I finished working with this technology 6 or so years ago and with what I would consider more rudimentry versions, and they kept historic faults stored until they were either fixed and cleared or self "repaired". Intermittent if you like.

Also where would someone like the OP get his hands on exactly what code Pxxxx means without the software available to dealerships?
Does the Scangauge have this info for whatever vehicle it is plugged into?

AnswerID: 614853

Follow Up By: RMD - Wednesday, Nov 08, 2017 at 15:24

Wednesday, Nov 08, 2017 at 15:24
If you have a list of the codes, it will point to a fault in that system.
The Scangauge or similar only displays the info stored in the ECU memory.
All good if the fault is a component or sensor, but if it is an itermittent connection type fault the ECU may not record anything as wrong or more importantly it may indicate many sensors are at fault.

My local Nissan dealer had a Navara which indicated multiple sensor faults all at the same time, in a near new vehicle which stopped and would not start. After fiddling with wiring and negative earthing points it was then perfectly OK and indicated NO Faults present after they were initially cleared.
The unfortunate thing is, the owner then wanted to trade it in for another vehicle and was told the dealership wouldn't trade it because it had faults. The faults never happened again. He bought a different brand of vehicle, disgusted with that previous brand.
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Follow Up By: Dean K3 - Wednesday, Nov 08, 2017 at 19:47

Wednesday, Nov 08, 2017 at 19:47
I purchased a portable OB2 reader kingchrome from memory.

Bit hard to remove a ahrd wired unit to assess code fault on another vehicle

in the booklet of "how to use it" is a comprehensive list of commonly used codes

starts at: P0001 fuel volume regulator control circuit open

ends at P0999 shift solenoid F control circuit High

and a plethora of others in between -hard part what happens if manufacturers use more than 999 errors in the future
FollowupID: 885560

Follow Up By: pop2jocem - Wednesday, Nov 08, 2017 at 20:25

Wednesday, Nov 08, 2017 at 20:25

If my memory serves me, each sensor and it's associated wiring, plugs and connection points worked on a supply voltage commonly around 5v + -. There was then an operating "window" to supply the ECU information that it considered along with other inputs and compared to it's "mapping" for want of a better description.
Any reading above or below it's set parameters resulted in a fault code being generated. This code was then stored for later retrieval by some form of hard/software such as a Scangauge. To interpret the code or codes you obviously needed a list which translated into language the technician could work with.
The software we were provided as a dealer for the particular piece of equipment we were dealing with, American in origin in our case, came with the interpretation of the various fault codes and a possible "follow the bouncing ball" series of suggestions to find and correct.
All good if you had the interpretation of the various codes. Pretty meaningless for the average bear if you didn't.
I am not familiar with the Scangauges and what info they may provide other than a list of Pxxxx numbers.
Do they give interpretations such as "throttle position sensor voltage high/low" ??

FollowupID: 885561

Follow Up By: RMD - Wednesday, Nov 08, 2017 at 21:11

Wednesday, Nov 08, 2017 at 21:11
I think all you get is the P code number, the rest you work out by having other info.
When my boost chamber hose fell off, it only gave a code of low boost, I had to find why.
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Follow Up By: pop2jocem - Wednesday, Nov 08, 2017 at 21:53

Wednesday, Nov 08, 2017 at 21:53

I guess in your situation you knew, or were able to ascertain, that the code number thrown up by the vehicle in question indicated a low boost situation. My point being that without that knowledge, it's just a number.

We were also given the resistance values across the pins of each sensor and the values at the ECU so that we could isolate a sensor fault or a wiring harness fault.
To carry out these test all that was needed was a multi meter.

One of the first items we were always instructed to test for was that the vehicle had a fully charged battery and supply voltage to the ECU before starting any diagnostic procedures.
It's amazing how many so called techs I came across who failed to check that very basic first step.

FollowupID: 885564

Reply By: Member - J&A&KK - Thursday, Nov 09, 2017 at 01:15

Thursday, Nov 09, 2017 at 01:15
Hi Shep

I have had my 2014 Prado serviced by Newtown Toyota in East Victoria Park Perth. I am fussy about servicing and want to know causes and issue rectification. From my experience I would recommend you give them a call.

All the technical reasons as to why you are having the problem is best left to others to speculate. Trust you end up with a good result.

AnswerID: 614859

Follow Up By: RMD - Thursday, Nov 09, 2017 at 08:36

Thursday, Nov 09, 2017 at 08:36
That doesn't give any help as to what Shep's problem may be. Going to a service centre where they scan it and hopefully Identify and correct the problem is available to anyone. Not much help when out on the road though. Some background possibles are uselful to check. He may then be able to correct it himself at no cost or greatly reduced cost.

Having a problem and only seeing a signpost isn't going to fix it.
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Follow Up By: Member - J&A&KK - Thursday, Nov 09, 2017 at 23:03

Thursday, Nov 09, 2017 at 23:03

True. However I was only replying to the last paragraph of the original post.

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Reply By: Zippo - Thursday, Nov 09, 2017 at 17:02

Thursday, Nov 09, 2017 at 17:02
It doesn't need a diesel mechanic to check codes. Depending on what your timetable and preferences are, Supercheap have a "connect and detect" service and they have a store in Esperance. They *may* have enough info on the listed code meanings to be able to provide you with some clues.
AnswerID: 614868

Follow Up By: Shepbar - Saturday, Dec 02, 2017 at 10:19

Saturday, Dec 02, 2017 at 10:19
This is a late follow-up to let everyone know that the problem has been fixed.
John Dougherty of Port Kennedy Automotive Repairs 08 9524 6777 changed the Acceleration Assembly which is the module attached to the accelerator pedal and sends the drive-by-wire signal.
John was able to nail the problem after interpreting the scan code and drawing on his experience to pinpoint the issue; it was far from straight forward and I'd have no hesitation in recommending this switched on mechanic to forumites.
Thanks again to the above forum contributors who took the time to help me.
Cheers, Shep
FollowupID: 886235

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