What Is Wrong With My Yaris?

[fyviebird]

I am hoping someone can shed some light on my broken down Yaris. It has been in the garage for 2 weeks now and is no better.

It started mildly bunny hopping, for want of a better expression, and the power steering light would come on and the power steering would fail. This bunny hopping got progressively worse until the car stopped running completely (luckily by this stage it was at the local garage).

It was towed to a Toyota dealer who plugged it into the diagnostic machine and diagnosed a failed power sterering ECU. This was replaced at a cost of £100 + labour (another Toyota dealer quoted my £500 for the same part which seems a bit odd) and the car appeared to be fixed. It was driven 40 miles back from the dealer on Monday and I collected it Monday night. Drove it 10 miles on Tuesday with no probs then it started chugging again (less violently than it had been before). However after stopping it failed to start again and is back at the garage.

When I say it fails to start the engine will turn and fire but it seems incapable of keeping going. Even if you rev the engine it still stalls. The local mechanic has identified a fuse that keeps blowing (this seems to be a separate fuse from the rest that sits above the fuse box). Replacing this however does not seem to cure the problem.

My current bill sits at £350 and we are no further forward.

Anyone have any ideas?

[Caz SR]

Hiya - a Moderator may move this into the Yaris forum so you can get more help.

How old is the car? I'm guessing it's out of warranty if you're forking out repair costs?

[Bibbs]

Already moved Caz .. was *also* posted in the Yaz forum, so I've removed that one.

[Caz SR]

Cool Bibbs B)

[fyviebird]

Hiya - a Moderator may move this into the Yaris forum so you can get more help.

How old is the car? I'm guessing it's out of warranty if you're forking out repair costs?

Hi

My yaris is a 2001 Y reg model, early 2001 so way out of warrantly unfortunately.

[mcsky]

unsure about the power steering etc, but my yaris recently was bunny hopping lolz, it feels as if ur putting yout foot down on the accelarator but then u cant get power out of it and u chug a long. well my problem turned out to be the air flow meter.

i took it to toyota and they ran it on the diagnostic machine but it didnt actually detect it. i had to take it in another day so they could do a more thorough check and then found it was the air flow meter giving wrong readings etc explaining the bunny hopping. hope this helps

[Bee]

The power assisted steering (PAS) system can be considered as an add-on extra to the original base machine. When PAS fails, at its worst, turning the steering wheel requires a bit more effort, that's all -- did you not feel the difference? The engine performance or behaviour is not affected; the whole engine system simply reverts to that of a base machine. In your case of engine failure following a failed PAS system (or vice versa), I would suggest that they were unrelated and were mere coincidence.

The causes of hesitant running and stalling are protean, ranging from those arising from the ignition system (timing advance/pulse duration -- the Dwell time), the air intake (engine loading; mcsky has already mentioned the Air Flow Sensor), the fuel supply (from the tank to the injector timing/action pulse width), the other engine sensors (there are many which act together to ensure smooth engine running) to of course the Electronic Control Module itself. The most expedient course of action is to have engine diagnostic tests at a reputable garage (not necessarily Mr T) equipped with proper electronic diagnostic tools. Hopefully a simple initial Fault Code Finder scan will quickly reveal where the problem lies (unless the fault is persistent and serious enough, it may not cause a fault code to be logged though; on the last occasion, it threw up PAS failure and nothing else), from where further search can be pursued to pinpoint the precise fault(s). If not, the entire lengthy process has to be completed and is therefore costly.

I'm sorry this sounds vague, but there is little clue to go on with so far. Except one: there is a recurrent blowing out of a fuse. I could not identify the one that "sits above the fuse box", for there isn't one. Which fuse box? In the storage tray in front of the driver or in the engine bay? What colour is the fuse (the current rating is colour coded)? Which electrical circuit(s) does it serve? What did the mechanic tell you about this fuse? Did he look further? He did not just replace a blown fuse, or did he? Also important: under what previous circumstances has this same fuse blown? Or, did they all happen with the same mechanic? Information on the car's capacity, mileage, date of last MOT pass, past accidents....etc. may also prove useful.

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Bee.

[grass777]

Power steering pumps can fail by siezure and locking up this might stall a small 1 ltr engine and make it hard to keep running.

Before replacing any expensive power steering ecu (i cant see why any power steering would need an ecu to work anyway is this true?) I would take the power steering out of the equation (take belt off power steering pump) then see if the car runs ok...

but i would think this problem you are having might be some engine electrical fault (leads, plugs, sensor or engine ecu)

start with cheapest first.

when the engine stalls on its own accord it would seem like the power steering has packed up because the engine is no longer turning the power steering pump and if this happens when you are travelling fast you would have a long way to roll with no power steering...

sorry i cant be of more help as i have mainly worked on big diesel's not petrol's...........

[Bee]

Power steering pumps can fail by siezure and locking up this might stall a small 1 ltr engine and make it hard to keep running.

Before replacing any expensive power steering ecu (i cant see why any power steering would need an ecu to work anyway is this true?)...

when the engine stalls on its own accord it would seem like the power steering has packed up because the engine is no longer turning the power steering pump and if this happens when you are travelling fast you would have a long way to roll with no power steering...

It is hard to accept your suggestion that the PAS pump pulley might have siezed causing secondarily the small engine to fail. The engine though tiny is very powerful. It is more likely that the serpentine belt would slip on the pump pulley rather than the pump pulley stopping the crasnkshaft from turning.

Your latter suggestion is more reasonable. You are saying that in essence the engine failed primarily causing a secondary malfunction of the PAS. There was no mechanical defect in the PAS. That implies the OP was cheated for the 'repair' of a normally working PAS. OK...This is not unheard of! Odd thing was the Battery light did not come on, for the serpentine belt links the crankshaft pulley with the PAS pump, the alternator, the water pump, and the air conditioning compressor (if fitted) together. An alternator working below par, producing less than the normal current output, could not have caused a blown fuse. It would be interesting to know what that fuse was for which circuit, and why there was excessive current passing through it.

I have no knowledge that the PAS has any ECU connection. :)

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Bee.

[fyviebird]

Hi

thank you all for your help

I got my car back last night after a second trip back to the Toyota dealer. After a lot of scratching of brows someone suggested replacing the power steering relay unit and hey presto the car jumped back to life again. The power steering ECU they had initially replaced does not seem to have been damaged by this second failure to run which makes me wonder if the initial ECU was damaged at all - although it did show up as being damaged on their initial diagnositc test, and didn't show up yesterday when it was back there again, no faults showed up on that second diagnostic scan. Toyota did not charge me for the relay unit or time spent scratching their heads which I think is only fair but also quite pleasantly surprising knowing what main dealers can be like!

Apparently the power steering system controls fuel flow to the engine, sending more fuel when the steering assistance is needed, so if it is faulty then the fuel to the engine is disrupted. It's all gobbledegook to me but might be of interest to those more mechanically minded out there.

So, it's running fine again for the moment, fingers crossed!

Thanks again

[Bee]

...Apparently the power steering system controls fuel flow to the engine, sending more fuel when the steering assistance is needed...

Hah! I am flummoxed!

Thank you for tidying the loose ends. I'm learning everyday.

Now, why is the fuel input needed to be adjusted on turning the wheel? Sending more fuel not cutting down the precious liquid is equally surprising! Any comment from anyone?

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Bee.

[grass777]

...Apparently the power steering system controls fuel flow to the engine, sending more fuel when the steering assistance is needed...

Hah! I am flummoxed!

Thank you for tidying the loose ends. I'm learning everyday.

Now, why is the fuel input needed to be adjusted on turning the wheel? Sending more fuel not cutting down the precious liquid is equally surprising! Any comment from anyone?

--

Bee.

well i supose more fuel would be needed to stop the power steering pump from labouring the engine and posable stalling it.

in a truck there is no electronic parts at all just power steering pump , steering box ,thats it .........ecu ,stange

good to see they got it sorted !

[Blue84]

Glad to see it's finally been sorted :)

[Black Knight]

Highest load on the steering is normally going to be during manouvering (i.e. very low speeds). Since the power steering is driven off the pump I guess it needs to be running at a certain speed to help you as much as possible.

[rutland32]

Hi

I had bad hopping on my yaris, found it to be a sheared bolt on the air filter box. it kept breaking the seal over the air inlet causing it to hop. It may help.

[mcsky]

glad the problem is sorted, ah so that explains why u can hear the car rev when your stationary and u just turn the steering wheel without touching the accel

[gump2000]

glad the problem is sorted, ah so that explains why u can hear the car rev when your stationary and u just turn the steering wheel without touching the accel

before i had my mr2 i had a black 2 door yaris gs. and i found that if you put the steering on full lock then kept bouncing it off full lock, i.e tweaking the wheel on full lock , you could get the engine to rev up.

[andy_moza]

I had the exact same problem as yourself only this week!!!!

See my post http://toyotaownersclub.com/forums/index.php?showtopic=52280

Well anyway the RAC came out and figured that there was no power going to the fuel pump so they towed me to Toyota @ Star City, Birmingham where it turned out to be nothing more than a blue 15A fuse underneath the steering column.

It cost 44p, however with labour the total was £40 which I intend to claim back from the RAC as really being something that simple they should have surely found that out. My car was only in the garage one day and it was fine. I've had it back since Weds now and done over 80 miles in it and had no further problems.

Get all of your fuses inspected, and also get someone to see if there is a live feed going to your fuel pump, the connection is located under the rear seat.

Good Luck and let me know the out come.

My email is andy_moza@hotmail.com and I would be happy to answer any more questions!!!