GR Yaris Inconsistent Boost

[sixtentouge]

Has anyone who’s suffered from this issue changed the MAF sensor yet? I wonder if the P/N has been superseded or if there is a variance in part numbers between manufacture years etc? I maybe barking up the wrong tree but surely it’s just a case of software & sensor outputs?

It's not a MAF sensor issue. It's a re-map issue. That's why the 20 minute "reset" restores everything. You go in and start monkeying with boost targets and what not, only there's a lot of modeling going on in the background. Turbine speed, exhaust temperature, and even EMAP are modeled in this ECU. So it doesn't like sensor input that it's seeing from the increased boost. "If-Then" no longer equals "Goto," and starts doing strange things. But because other things that have been changed, the things it tries to do have strange effects on other things and it cascades into a place that's way outside the original operating parameters. The ECU has learned its way into a corner, so to speak.

So you reset the ECU and all of the learned data is reset back to where it all works again. But it'll eventually learn back to not working again. I've seen this sooooo many times here in Japan. Do re-maps give people more power? Sure. But the hope is that the quality of the re-map, or the place the outputs end up doesn't end up putting a piston in the oil pan.

 

[Sekred]

Faulty Boost control solenoid caused these messages and full limp mode.
Toyota dealer had the car for 3 months and unable to diagnose.

 

[JJ.King]

I do love my MST , and it’s cost a lot, I have put std std airbox on and it’s the same, have disconnected the battery for an hour, but not tried it yet, as my back has failed me!
I can see me going ecutec or syvecs, I intend to keep the car so will have no issues in the future

When I first put in my MST intake the issue didn’t happen straight away. The car drove like normal for a couple months. I think give the stock ecu time to readjust and visit local dealership to see if they can reset anything from their half?

Ecutek, Syvecs or Motec, can’t go wrong haha. I have heard/seen on that after a few years tuned on Ecutek that the stock ecu starts to slowly pull back power to original. I think only a couple cases of this and not a negligible amount to worry over, but good to note

 

[Woody]

Well after 3 1/2 years I have solved my inconsistent boost issues ever since the first day of driving.

After many mods and ecutek remap I still felt the engine didn't respond the same every time I drove it . Yes it was fast , but not just right . Acceleration wasn't the same every time. Even though after the remap the boost gauge looked right .

After seeing an article I have Purchased a genuine Toyota GR Yaris Boost Sensor from whifbitz. I have learnt these fail regularly, symptoms are no boost and erratic boost.

Replaced myself ( very simple ) and the car is brilliant. The throttle pedal is so much more responsive and it accelerates the same every time.

If your having the same issues it's worth a try for £150 .

 

[GR.KEV]

Well after 3 1/2 years I have solved my inconsistent boost issues ever since the first day of driving.

After many mods and ecutek remap I still felt the engine didn't respond the same every time I drove it . Yes it was fast , but not just right . Acceleration wasn't the same every time. Even though after the remap the boost gauge looked right .

After seeing an article I have Purchased a genuine Toyota GR Yaris Boost Sensor from whifbitz. I have learnt these fail regularly, symptoms are no boost and erratic boost.

Replaced myself ( very simple ) and the car is brilliant. The throttle pedal is so much more responsive and it accelerates the same every time.

If your having the same issues it's worth a try for £150 .

Yeah had the same, fitted another and it flys

 

[Sekred]

So how does this boost control solenoid work.

Basically it opens and closes for a controlled time. This is called duty cycle and is measured over 1 second. If its open for half a second and closed for half a second the duty cycle is 50%.

Generally boost control solenoids open and closed around 20-30 times a second. This is the hertz rate and this hertz rate is needed to provide a smooth boost response.

Lastly, the boost control solenoid is controlling the speed of the Turbine not the actual boost pressure. The speed of the turbine, increasing speed and slowing as the solenoid opens and closes controls the boost pressure. You can see how a faulty/sticking solenoid can cause inconsistent boost response.

 

[CerN]

Well after 3 1/2 years I have solved my inconsistent boost issues ever since the first day of driving.

After many mods and ecutek remap I still felt the engine didn't respond the same every time I drove it . Yes it was fast , but not just right . Acceleration wasn't the same every time. Even though after the remap the boost gauge looked right .

After seeing an article I have Purchased a genuine Toyota GR Yaris Boost Sensor from whifbitz. I have learnt these fail regularly, symptoms are no boost and erratic boost.

Replaced myself ( very simple ) and the car is brilliant. The throttle pedal is so much more responsive and it accelerates the same every time.

If your having the same issues it's worth a try for £150 .

Pardon my stupid question, but where is this sensor located?

My car has also been inconsistent since day 1, but I always thought it was due to stock ECU tune being very sensitive to temps, fuel quality etc.
Would like to try swapping this sensor myself. Worth a shot.

 

[Michael Knight]

Pardon my stupid question, but where is this sensor located?

My car has also been inconsistent since day 1, but I always thought it was due to stock ECU tune being very sensitive to temps, fuel quality etc.
Would like to try swapping this sensor myself. Worth a shot.

is it the solenoid top left on top of engine, that adjusts the wg?

 

[CerN]

is it the solenoid top left on top of engine, that adjusts the wg?

View attachment 31561

Looks like it! Thanks.


That is probably easy enough to swap even for me

 

[Michael Knight]

Looks like it! Thanks.


That is probably easy enough to swap even for me

Its quite easy yes

 

[GRBadger]

Well after 3 1/2 years I have solved my inconsistent boost issues ever since the first day of driving.

After many mods and ecutek remap I still felt the engine didn't respond the same every time I drove it . Yes it was fast , but not just right . Acceleration wasn't the same every time. Even though after the remap the boost gauge looked right .

After seeing an article I have Purchased a genuine Toyota GR Yaris Boost Sensor from whifbitz. I have learnt these fail regularly, symptoms are no boost and erratic boost.

Replaced myself ( very simple ) and the car is brilliant. The throttle pedal is so much more responsive and it accelerates the same every time.

If you’re having the same issues it's worth a try for £150 .

Pardon my ignorance but why have you bought a replacement sensor yourself when surely a failing part would be covered under warranty? I wouldn’t consider than a consumable part so no way would I stump up for a new one.

 

[Woody]

Pardon my ignorance but why have you bought a replacement sensor yourself when surely a failing part would be covered under warranty? I wouldn’t consider than a consumable part so no way would I stump up for a new one.

I have been to Toyota quite a few times with the issue of erratic boost . They come back and say it's fine . I thought for £150 and fitting it myself it would be easier and less hassle. Definitely works for my car .

 

[GRBadger]

I have been to Toyota quite a few times with the issue of erratic boost . They come back and say it's fine . I thought for £150 and fitting it myself it would be easier and less hassle. Definitely works for my car .

I’d go back to Toyota and ask to speak to their master tech and present them with a bill for self diagnosing and a refund for the price of the replacement part or at least a heavy discount on the next service as no way would I be happy paying out £150.

 

[Woody]

Pardon my stupid question, but where is this sensor located?

My car has also been inconsistent since day 1, but I always thought it was due to stock ECU tune being very sensitive to temps, fuel quality etc.
Would like to try swapping this sensor myself. Worth a shot.

It's not difficult, first remove engine cover . The sensor is top left on the engine. Slip off the two boost pipes carefully, this is the tricky part as they are tightly fitted. I slowly eased them off with a flat head screwdriver while pulling the pipe. Then unplug the electric part and unscrew the retainer bolts . Then replace with a new sensor.

Picture attached below

 

[CerN]

Received mine today. Took 5 minutes to swap over.

Too early to say anything at this point, only done one short drive, but the car felt great. Every pull felt the same, and they didn't have any hesitation. Sample size of one isn't enough, but I will report back after I have driven more.

 

[Sturesmyg]

Received mine today. Took 5 minutes to swap over.

Too early to say anything at this point, only done one short drive, but the car felt great. Every pull felt the same, and they didn't have any hesitation. Sample size of one isn't enough, but I will report back after I have driven more.

what’s your thoughts now? If it’s a significant difference, will you consider warranty claim?

 

[CerN]

what’s your thoughts now? If it’s a significant difference, will you consider warranty claim?

I haven't been driving very much lately, so I don't want to report too early, but over the few drives I have had the car has been spot on.

I never complained to my dealer in the first place, so I won't go that route. They should have had a chance to fix it first.

 

[CerN]

I think I've done enough drives now to say with confidence that changing the boost sensor/solenoid changed my car for the better. It has pulled evenly every time I have floored it. No slight hesitations while climbing the revs that I had off and on in the past. Car doesn't have days where it feels slower anymore.

 

[Sturesmyg]

I think I've done enough drives now to say with confidence that changing the boost sensor/solenoid changed my car for the better. It has pulled evenly every time I have floored it. No slight hesitations while climbing the revs that I had off and on in the past. Car doesn't have days where it feels slower anymore.

Shit. How should I proceed with this towards Toyota Norway? Not asking only @CerN here. Asking everyone I guess.

 

[nikoel]

I was driving my GR the other day thinking to myself. Man I have gotten used to the power. It just doesn’t feel like it did back then. Fast forward to today. Put the foot down and left my stomach behind - all that power out of nowhere

So anyway; had enough of this - just wanted to post this in case it’s useful. When I went to order a replacement solenoid I was told that my part number 25819-0W010 was superseded by 25819F0010

Looks like Toyota have at least realised that they needed a better part

Or hell - it’s a cheaper part for more money. Like the rest of things you buy these days