Fault code 76. Dbw ethrottle tps tracking error

[Srdat1600]

Hi guys

Need help with plug n play. G4x. Bosch dbw.

Code 76...

Calibrates ok.

Tracks nice. Bit off at the start. Works well until going into on mode. Dont touch the throttle and within 2 secs code 76. Any help appreciated. 

Thanks in advance

[Confused]

You'll need to post tune, plus PC logs capturing all parameters.

The log should probably contain (at the least) it working "correctly" in Setup mode, with varying throttle positions, slow sweeps plus faster changes etc, and it going into ON mode and showing the fault.

A comprehensive log file showing the issue will help you get some advice and a resolution quicker.

[Srdat1600]

1 hour ago, Confused said:

You'll need to post tune, plus PC logs capturing all parameters.

The log should probably contain (at the least) it working "correctly" in Setup mode, with varying throttle positions, slow sweeps plus faster changes etc, and it going into ON mode and showing the fault.

A comprehensive log file showing the issue will help you get some advice and a resolution quicker.

Ill get it uploaded asap.

Thank you

[Adamw]

76 is TP sub/main tracking error.  Since it happens as soon as you switch on the safeties I would say it is the TPS (Sub) 100% setting.  

Make sure it is set to 100% if both sensors move all the way to 100% or if they dont then set it to whatever value of TP main the TP sub stops increasing.

[Srdat1600]

8 hours ago, Adamw said:

76 is TP sub/main tracking error.  Since it happens as soon as you switch on the safeties I would say it is the TPS (Sub) 100% setting.  

Make sure it is set to 100% if both sensors move all the way to 100% or if they dont then set it to whatever value of TP main the TP sub stops increasing.

Hi adam.

Your a genius and absolutely 100 percent correct. One was set to 0 percent.

Amazing. Thank you.

[Brad Burnett]

Not to create another thread regarding ethrottle, but what happened to all the error accumulators for the ethrottle? AP, TP, TP/target?  

[Adamw]

11 hours ago, Brad Burnett said:

Not to create another thread regarding ethrottle, but what happened to all the error accumulators for the ethrottle? AP, TP, TP/target?  

Yeah, they are not available at the moment due to the different way the safety system works in G4X, it was assumed by the firmware guys that they werent needed/used but it was one of the first things I complained about after tuning my first G4X.  So it is on the list to add some similar functionality back in or develop some new diagnostic tool so you can more easily see how close you are to breaking the camels back.  It is still a little while off, looks to be scheduled for 6.19 firmware. 

[Brad Burnett]

1 hour ago, Adamw said:

Yeah, they are not available at the moment due to the different way the safety system works in G4X, it was assumed by the firmware guys that they werent needed/used but it was one of the first things I complained about after tuning my first G4X.  So it is on the list to add some similar functionality back in or develop some new diagnostic tool so you can more easily see how close you are to breaking the camels back.  It is still a little while off, looks to be scheduled for 6.19 firmware. 

Oh man.... here i am with a ITB 1uz with that single ATPower actuator, im sure you can imagine the struggle with out those values.

Was a big surprise when i went to set up my usual DBW diag page and those values weren't there. 

"Am I just supposed to hope and pray and shoot in the dark?" were the exact words that came out of my mouth.

[Adamw]

The tuning process isnt much different than it was in G4+, I just found those error accumulators good for looking at logs after the first drive or racing event.  For the PID tuning you are in set up mode anyhow so the error accumulators were never working in set up mode.  Once you  have the PID controlling throttle position well in the log then a good way to test is to drop the fault delay to 0.5s, if you dont get any errors with heavy foot work then change it back to the default 1s and you are good to go.  

[Brad Burnett]

I totally get that.  Its just as you said, the error accumulators are just great for double checking your work.

Any idea if its possible to add the parameters that surround the Fault code 84, IC over temp/current?  Would be very curious to see what kind of amps/temp things are being worked at.

[Aqmar]

Greeting @Adamw,

I realize this thread was discussed nearly 3 years ago, but I don't want to open a new thread as the issue is about Fault code 76.

My Engine is 2GRFE in Toyota MR2 SW20. The Engine is still in OEM setup. 

The problem here is I experience Fault Code 76 randomly while driving. I have tried to calibrate the TPS a few times. Adjust the PID, and it seems the TPS(Main) and eThrottle Target are spot on.  Check the wire connection, and it seems fine.  I have read through some of the threads here but can't seem to identify what could be the cause of this trouble.

Maybe there are areas that I have overlooked. So I attached here 3 of my data logging, which I managed to catch when the fault code happened. Also my Base Map is attached here as well.

Your assistance is very much appreciated.

 

PC Datalog - 2023-05-12 8;17;19 am.llgx PC Datalog - 2023-05-12 8;25;20 am.llgx PC Datalog - 2023-05-12 8;29;43 am.llgx 2GR MR2 test 6a.pclx

[Adamw]

It looks like you have a fairly poor connection so the logging rate is pretty slack in a lot of areas, the detail around the failures is not good enough to see if the chicken or the egg came first.  The TP tracking error occurs because the TP sub voltage drops below your AN Volt 2 error low value which puts AN Volt 2 in volt and sets the TP sub to 0%.   What I cant tell from the log is whether it is just the error low setting that is too close and a small amount of undershoot occasionally crosses the error low - or if there is a problem with the wire or sensor that causes the voltage to drop out sometimes. 

So start by adjusting the error low on both AN Volt 1 & 2 to 0.05V, and add the list of channels below to your ecu logging set so we get some better detail if it happens again. 

• AN Volt 1 & 2 raw voltages 100Hz.
• E-throttle motor DC, E-throttle target, TPS main & sub, APS main, TP/Target error accumulator, TP tracking error accumulator, Aux9/10 supply, Ign 8 status, Fault code status.  50Hz.

[Aqmar]

10 hours ago, Adamw said:

It looks like you have a fairly poor connection so the logging rate is pretty slack in a lot of areas, the detail around the failures is not good enough to see if the chicken or the egg came first.  The TP tracking error occurs because the TP sub voltage drops below your AN Volt 2 error low value which puts AN Volt 2 in volt and sets the TP sub to 0%.   What I cant tell from the log is whether it is just the error low setting that is too close and a small amount of undershoot occasionally crosses the error low - or if there is a problem with the wire or sensor that causes the voltage to drop out sometimes. 

So start by adjusting the error low on both AN Volt 1 & 2 to 0.05V, and add the list of channels below to your ecu logging set so we get some better detail if it happens again. 

• AN Volt 1 & 2 raw voltages 100Hz.
• E-throttle motor DC, E-throttle target, TPS main & sub, APS main, TP/Target error accumulator, TP tracking error accumulator, Aux9/10 supply, Ign 8 status, Fault code status.  50Hz.

Alright, as per your advice, for a start, I have adjusted the AN Volt 1 & 2 to 0.05V. I wanted to attach the base map, but then the total file attached here has exceeded the allowable size. But basically, the base map is still the same, only that it has a lower error for both AN Volt 1 & 2.

I think the more important file here is the ECU logging. It has happened again today twice. Attached herewith are the 2 occasions that the same problem occurs. I hope the resolution is good enough, as I have set the logging frequency according to your proposed Hz. 

ECU Internal Datalog - 2023-05-12 10;42;10 pm- 1st Occasion.llgx PC Datalog - 2023-05-12 10;38;43 pm 2nd Occasion.llgx

Sorry,

There are suppose to have 2 ECU logging file but the 2nd file was 2 big to be attached. Therefore i can only attached the 1st occurance. If these file is still not sufficient, let me know how can i attach a bigger size of file to share the 2nd occurance.

[Adamw]

Neither of those files have attached correctly.  You can delete and reload or use a file sharing service like google drive or similar.

[Aqmar]

Hi @Adamw,

This is my first time sharing a file using google file-sharing link. I hope I get it right. There are supposed to be 5 files inside this link of the folder that I shared:

1. 2 ECU Log file (1st occurrence and 2nd Occurance)

2. 2 PC Data log file (1st occurrence and 2nd Occurance)

3. 1 Base map file .pclx

 

https://drive.google.com/drive/folders/1iG6RFhXmqONpMl_Y9Y9jXXZ5cikBweNK?usp=share_link

[Adamw]

The files are restricted.  Go back into the sharing settings and choose the option that is something like "anyone with link".

[Aqmar]

7 hours ago, Adamw said:

The files are restricted.  Go back into the sharing settings and choose the option that is something like "anyone with link".

Sorry @Adamw

.ok done with the access settings 

[Adamw]

Ok the TP sub voltage starts reading much lower than it should in the areas where it fails.  It could be a loose connection or failing TP sensor, but since you have =3 logs here showing it failing at idle position I think that points more towards the sensor - they usually wear out around the idle area first.  

[Aqmar]

Thanks, @Adamw. It seems, based on your finding, it is more towards the symptom of a wearing-out TP sensor. 

Just to be sure myself and learn something about what happened here, what does it mean by a loose connection here? Does it from a loose wire connected at the connector or a loose connector? I have tried to test the wire at the connector, and it grips firmly and snugly, and the connector is still new and has that click when inserted into the throttle body socket. 

Just attached a picture here for reference. It seems, to change the TP sensor; one needs to change the whole set of the throttle body.

 

[Adamw]

Yes, a worn TPS generally means replacing the throttle body.  As for "loose connection", it could be anywhere - a bad crimp, broken wire, loose terminal, bad splice etc.  A quick test you can do is set up a blank page on your laptop screen with two very large gauges showing just TP Sub and TP main on the screen.  With Ign on, engine off go around all the relevant parts of the loom and shake/pull/yank/bend/wiggle etc while watching the screen, if you see either TP suddenly signal change when you are doing that then that would suggest a bad connection in that area.  This testing needs cover as much of the path as possible - so ecu end of the loom, TP end of the loom, anywhere there are splices for the 5V or Gnd and the general path from ecu to TP.  

[Aqmar]

Thanks, Adam for the advice.

I have tried my best to follow the advice given. I even went to the extent of cleaning the 2GR Throttle Body. The connection seems fine. Just to share here, I also tried increasing the TPS error value to 20%. It was set to 0% before this:

Been driving for more than a month now, and thankfully no Fault code 76 has happened so far. I can say so far is so good. But I do take note of the Throttle Body to wear n tear. So I will try to keep one on standby when in need.