the dreaded throttle control error codes

[RPGs818SNA]

I agree with your analysis, Rick. With the engine off, it should just be the pedal, throttle control, ECM, and relay. There are a few mid-wire connectors that need to be good too. I’d put a voltmeter on the pins of each of those components to see which signal is jumping around making the throttle jump around. I was sure hoping it would be a loose ground, but now I’m hoping it’s a bad connection somewhere that’s easy to find and fix. I’m hoping it’s not the ECM. Here are the relevant schematic pages so all can follow along.

Engine wiring turbo 03.jpgEngine wiring turbo 06.jpgEngine wiring turbo 09.jpg

Wish you the best of luck finding this gremlin.
RPG

[Ajzride]

I believe there is a primary and secondary signal from the pedal to the throttle body, check that they are in sync.

[Bob_n_Cincy]

I removed the original one and left it connected and positioned so I could see it through the rear window. With the ignition on and slowly flooring the pedal, the throttle would open fully some of the time. Sometime it would then go to about 1/8" open and only go from closed to that position even when flooring the throttle. Cycling the ignition on and off would sometimes return it to normal operation (opening fully) and sometimes it would only open that 1/8". When I swapped throttle bodies the "new" one did the same thing. Sometimes it would fully open with the pedal floored and sometimes not.

The action you describe here is close to what I would expect from a pedal that doesn't have a travel stop.
After clearing codes or cycling power to the ECU the throttle body works fine until the first time the pedal goes into over-travel.
Over-travel causes limp mode. Try you test again but only go to 1/2 pedal each time.
Bob

[Bob_n_Cincy]

I believe there is a primary and secondary signal from the pedal to the throttle body, check that they are in sync.

Here are the voltages you should be looking for. pedal voltages.jpg

[FFRWRX]

The action you describe here is close to what I would expect from a pedal that doesn't have a travel stop.
Over-travel causes limp mode. Try you test again but only go to 1/2 pedal each time.
Bob

I'll try only 1/2 pedal, but....are you sure? Whenever it goes into limp mode while driving I am just cruising along not even altering the pedal much.

This came up earlier and I can't see how the pedal could over-travel. This is the pedal with the Hall effect sensors (or something like that inside, not the copper traces/wipers). There is a very solid stop built into the pedal assembly. Is it this pedal design that you've seen over-travel?

[FFRWRX]

Found an excellent video series on hunting down the limp home mode issue. This is part 3 where he finally solves it. He has an amazing amount of diagnostic equipment and really know his stuff.

https://www.youtube.com/watch?v=Mm0QJM8lbz0

What he shows is that the main relay powers up and then that powers up the throttle control relay. That allows the 12V to go to the ECM. Apparently that has to happen within 400ms or the system goes into limp mode. Spoiler alert on the video. He finds a loose connector on the back of a fuse box that prevents the 12V from consistently going to the ECM.

Screenshot 2023-09-06 at 5.04.11 PM.png

So the key is turned on and that sends 12V to the main relay (orange lines). That closes the contacts that allow the 12V to energize the throttle control relay (red lines). That pulls in the contact that flows the 12V to the ECM (green lines). This has to happen within 400ms. If that doesn't happen, or there is an interruption to the 12V to C1 on the ECM, it goes into limp mode.

So what makes sense (right now anyways) is for me to measure the voltage on pin C1 on the ECM and go through a number of key on/off cycles and do I get no initial voltage on that pin when it goes into limp mode.

[Bob_n_Cincy]

I'll try only 1/2 pedal, but....are you sure? Whenever it goes into limp mode while driving I am just cruising along not even altering the pedal much.

This came up earlier and I can't see how the pedal could over-travel. This is the pedal with the Hall effect sensors (or something like that inside, not the copper traces/wipers). There is a very solid stop built into the pedal assembly. Is it this pedal design that you've seen over-travel?

See the caption under this picture.
pedal stop.jpg
I experienced limp mode in my first 10 minutes of driving back in 2015.

[FFRWRX]

See the caption under this picture.
pedal stop.jpg
I experienced limp mode in my first 10 minutes of driving back in 2015.

I saw the caption under the picture. I also saw that it says that particular pedal design does not have a built in stopper. You have not shown the complete webpage where it shows the other pedal designs and it does not say the other designs don't have a built in stopper. Please see what I've written in post #45 and much earlier in post #5 where I show a picture of my pedal. The one you referenced states it is an STi pedal. Mine is a WRX, as shown in the 3rd picture on that webpage, which definitely does have a built in stopper.

So I'll ask again, are you aware of pedal over-travel with the WRX pedal design with the built-in stopper?

[lpmagruder]

For what its worth, I have a 06/07 pedal which is the next picture on that page. I've been driving around for a while with no additional stop and have been to WOT a few times at least and never seen it throw a code or go into limp mode. Fairly certain it's just that one pedal design that has an issue.

I do want to eventually build a stop because the sheet metal adapter bracket FF provides is pretty flimsy, and I don't like the idea of the force getting reacted that far up on the pedal long term, but that's just a reliability thing I think.

[Bob_n_Cincy]

So I'll ask again, are you aware of pedal over-travel with the WRX pedal design with the built-in stopper?

Rick, I have had both pedal designs in my car back in 2014. I don't remember exactly when I had the over-travel issues.
My trouble shooting method always revolved around attacking one DTC code at a time. Have all your codes been resolved?
Bob

The stopper for the plastic pedal was mounted to the floor/carpet. stopper.jpg

[FFRWRX]

My trouble shooting method always revolved around attacking one DTC code at a time. Have all your codes been resolved?

Normally I would agree with you Bob. But in this strange case I replaced the neutral switch which eliminated that code. Then replaced the speed sensor which eliminated that code. When it goes into limp mode and the codes related to the throttle pedal appear, so do those previously eliminated codes. So I think something is triggering a number of codes to appear, even though the main issue is not one of those components.

Going for a drive later to test out another theory.

Rick

[Bob_n_Cincy]

Rick, do you have have a actual wire from battery negative to engine block? Or are you going through the chassis?
Bob

[lance corsi]

I’ve been watching with interest. I’m glad I chose a cable operated tb.

[FFRWRX]

Rick, do you have have a actual wire from battery negative to engine block? Or are you going through the chassis?
Bob

My ground lead uses the frame. My reasoning is:

1) Millions of production cars do it this way and it works; including Subaru I imagine (though my car came with the donor stuff already stripped out so I don't know for sure).

2) The car starts fine which means the ground conducts a couple hundred amps without issue.

3) The ground lead at the battery is short and goes onto the frame; clean connection. There is a robust lead from the engine block to the frame at the rear.

4) If it was a ground momentarily losing contact, would it cause this exact symptom every time? Honestly, I have no idea.

I could run a booster cable clamped on the battery and the other end onto the engine, if I can figure a way to do that while leaving the car drivable; hood and rear deck lid partially open.

[FFRWRX]

My latest theory was this.

The throttle control relay directs power to the ECM. So if there is an issue with that, I think (from the video I referenced above) the car goes into limp mode. I accessed that relay and tested it; it tested fine. But I did notice it gets pretty warm. Not hot, but warm. Of course that might be normal since it is a metal encased one, not the usual plastic. My theory was that even though the relay tested fine, maybe after driving a bit it heated up and stopped working. So...

I soldered some leads onto the wires on the contact side of the relay; one going in and one coming out. I put a volt meter on the lead with power coming out (going to the ECM) and left that on the passenger seat and went for a drive. Of course the first drive the damn car wouldn't go into limp mode, but the second drive it did. But the voltage coming out of that relay did not change. So, another theory gone.

Nothing left to test that I can think of. When I get my computer back and can data log maybe I'll find something there.

Rick

[RPGs818SNA]

Well, it’s not the relay, so you’re one step closer to finding the culprit. That leaves the pedal, throttle control, ECM, and wiring. I just noticed a common ground from the ECM pin B30 RG to connector B83 which sends a ground to the pedal, MAF, both oxygen sensors, fuel temp, and fuel tank pressure. It’s called the Shield and Sensor Ground Joint Connector and is shown on page E/G(TB)-06. That’s probably worth measuring.

Incidentally, the 1.5” frame tubes have a conductance similar to 0 gauge (quarter inch) copper wire, and they form an interconnected network. So if you have good connections to the frame, you can’t do much better.

If the ECM pin B30 and connector B83 are good grounds, I’d try to monitor each pedal wire for smooth voltage change as you depress the pedal. Somehow the ECM seems to be getting a bad signal.

[FFRWRX]

I just noticed a common ground from the ECM pin B30 RG to connector B83 which sends a ground to the pedal, MAF, both oxygen sensors, fuel temp, and fuel tank pressure. It’s called the Shield and Sensor Ground Joint Connector and is shown on page E/G(TB)-06.

That is the one part of the wiring diagrams I find confusing. On the ground details, these are clearly grounding tabs:

Screenshot 2023-09-09 at 12.31.11 PM.png

On other parts of the wiring diagram, this is clearly a ground as well:

Screenshot 2023-09-09 at 12.28.58 PM.png

But what you are indicating I find confusing:

Screenshot 2023-09-09 at 12.25.05 PM.png

I know it states "ground joint connector", but it doesn't actually show it grounding anywhere. Following the 6 wires that come from the B83 connector, none of them go to a ground. The connector just looks like it connects them all together, but where do they ground? Or is B30 on the ECM a ground?

[RPGs818SNA]

Since the sensors produce an output relative to their ground, and the ECM measures that output relative to its ground, it's best to use a ground from within the ECM to ground the sensors. So ECM B30 is a ground from the ECM and is distributed to the sensors via B83 interconnections. B30 should measure low resistance to the other ECM grounds that go to the engine or frame.

[More detail than necessary] Each ground, whether engine, frame, ECM, or battery will have different sources and levels of noise on them. The engine has spark plug noise, the battery alternator noise, the frame lighting switch noise, etc. The ECM ground will have have noise based on what it's grounded to. But if it distributes that noisy ground to the sensors, they will add their signal to that noise, and the ECM will subtract its ground noise from the signal plus noise to get a clean signal from the sensors.

RPG

[Bob_n_Cincy]

Screenshot 2023-09-09 at 12.31.11 PM.png

The picture above are your intake manifold grounds.


pass side engine ground.jpg
This is mine on the passenger side


P1050128_grounds.jpg
This is mine on the drivers side


engine block ground.jpg
The (Subaru OEM) black wire with yellow stripe goes to may battery negative
The Other wire on the starter bolt is my ground strap to chassis frame.
bob

[FFRWRX]

The picture above are your intake manifold grounds.

I do have one on each side of the manifold. I'll take them off and clean them just to be sure they are good.

I'll see about checking the voltages at/from the pedal to see what I am getting.

I just noticed a common ground from the ECM pin B30 RG to connector B83 which sends a ground to the pedal, MAF, both oxygen sensors, fuel temp, and fuel tank pressure. It’s called the Shield and Sensor Ground Joint Connector and is shown on page E/G(TB)-06. That’s probably worth measuring.

Checked the resistance from pin B30 on the ECM connector to ground. No resistance, so things area good.

This would almost be fun if it wasn't so frustrating at times.

[FFRWRX]

engine block ground.jpg
The (Subaru OEM) black wire with yellow stripe goes to may battery negative
The Other wire on the starter bolt is my ground strap to chassis frame.
bob

I assume neither of these 2 wires are stock Subaru? I don't have anything on that bracket or starter bolt.

[Bob_n_Cincy]

I assume neither of these 2 wires are stock Subaru? I don't have anything on that bracket or starter bolt.

The black with Yellow stripe was out of my donor.


The other wire I made myself for the ground strap to the chassis.
Bob

[FFRWRX]

Got the computer upgraded and Romraider works now. I data logged a drive this morning and fortunately (?) it went into limp mode after driving for about 10 minutes. It's a huge CSV file, almost 12,000 lines.

Just had a very quick look at it and the first thing I noticed was that when it goes into limp mode the "accelerator pedal angle (%)" does not register properly. Before the limp it is accurate, cruising along it is around 10-15%, floored it is of course 100% with the "throttle opening angle (%)" being the same. After it kicks into limp mode, the pedal angle does not go above 9.02% (with a corresponding throttle opening of 14.08%) even when I am flooring it.

So, is it a normal thing whenever it is kicked into limp mode for any reason that the actual throttle pedal angle is not being measured? What is being shown is obviously a throttle pedal angle after some software manipulation.

This is pretty cool to be able to capture all this data. At least I have something to study now that will hopefully help.

I appreciate all the help to get me to this point.

Edit: "Main Accelerator Sensor (V)" goes to 0 when it goes into limp mode. It is above 0 every line before that.

Rick

[Ajzride]

The accelerator pedal has primary and secondary power feeds (B21 and B22),primary and secondary signals back to the ECU (B23 and B31), and redundant grounds (B29 and B30). It would take a lot of bad connections to result in 0V signal. I wonder if you have a bad pedal. Perhaps sit in the garage with the engine off key on while monitoring/logging all the signals while you work the pedal up and down for a few minutes and see if anything jumps out about the signal dropping to zero.

[RPGs818SNA]

Some have had success cleaning the pedal contacts with contact cleaner sprayed around the pedal pivot. It looks like yours may come apart for a more thorough cleaning. If it's a wire, it's likely the red one from pedal pin 6 to ECM B23.

[Bob_n_Cincy]

Just a note to help you troubleshoot.
The power to the pedal should be about 0.0v and 5.0 volts.
At zero pedal push the return signal should be around 1.0 volts.
At WOT the return signal sh0ould be around 4.0 volts.
These voltages should be referenced to the intake manifold as this is where all the sensor and ECU grounds terminate.
Bob

[lance corsi]

All this to eliminate a cable? I’m not a fan.

[lpmagruder]

If you want I can take a look at your file this evening. Not sure that I'll pull anything you haven't already though.

It's gotta be getting "something" otherwise you'd have no throttle control in limp mode, so it's weird that it would just show a flatline at 0v after that.

[Ajzride]

If you want I can take a look at your file this evening. Not sure that I'll pull anything you haven't already though.

It's gotta be getting "something" otherwise you'd have no throttle control in limp mode, so it's weird that it would just show a flatline at 0v after that.

Perhaps primary goes to zero and secondary is alive, causing limp mode due to only one signal? Would be nice to know what all will induce limp mode.

[FFRWRX]

The accelerator pedal has primary and secondary power feeds ... I wonder if you have a bad pedal. Perhaps sit in the garage with the engine off key on while monitoring/logging all the signals while you work the pedal up and down for a few minutes and see if anything jumps out about the signal dropping to zero.

A bad pedal would probably be my conclusion as well, except that I've replaced it with a new one (original Subaru part) and I suspect the person that did the original build replaced it before that. It seems to take about 10 minutes of driving before the limp mode kicks in. So it may or may not happen sitting in the garage trying it. I will be checking the voltage and grounds that you suggest, that are also in the Subaru diagnostic manual.

Some have had success cleaning the pedal contacts with contact cleaner sprayed around the pedal pivot. It looks like yours may come apart for a more thorough cleaning. If it's a wire, it's likely the red one from pedal pin 6 to ECM B23.

It's strange that I read that in so many places. I must be the only one that has pedal with no internal contacts. This is one of them taken apart. Some sort of Hall effect with a square magnet that rotates with the pedal. So nothing to clean inside it.

Screenshot 2023-09-15 at 7.09.29 PM.jpg

Just a note to help you troubleshoot...The power to the pedal should be about 0.0v and 5.0 volts...
Bob

Yes, I never did get around to measuring these voltages so I'll do that as the next step.

All this to eliminate a cable? I’m not a fan.

Not helping, Lance. The car came with that donor equipment already installed. If I had a choice I would have gone to a cable system long ago. But that is not a feasible option at this point.

--------------------------------------------------------------

The strange thing is that this happens after about 10 minutes of driving, and pretty much every drive. Something reaching a temperature that causes it? The coolant temp was pretty stable for a few minutes before this happened. If it was a loose connection or something like that, I would think it would happen at different times. And it is just cruising along when it happens; no bumps, no crazy throttle inputs. And to clarify a little as to what happens in the limp mode. The car will idle, but maybe a little slower than normal. When the pedal is pressed (a little or floored, makes no difference) the revs will go up to around 3,000 RPM max. So the car can be driven, but it is like you can only accelerate at just above idle power.

I put the file in Dropbox so if anyone wants to take a look, please do. There is probably a lot more data there than I needed, but since I wasn't sure what I needed I captured quite a bit.

Line 4290 is where I floored it and let it rev to 6,000 RPM and then backed off, shifted, and hit it again.
Line 10148 is the interesting one. That's where the limp mode starts and the accelerator voltage goes to 0.

File link in Dropbox: https://www.dropbox.com/scl/fi/yv563...qusl3rjcp&dl=0

Rick

[lpmagruder]

So I just pulled up your logs. My initial takeaway is that as soon as your main throttle position sensor loses voltage, the sub sensor voltage spikes. Maybe this was just you actually mashing the throttle since it went into limp mode, so maybe this is nothing. The vertical line I marked is when it happens.

2023-09-15 19_35_51-Window.png

Here's a real zoomed in view of right where it happened. I guess if it were me I'd probably frustratedly mash the throttle so maybe that's what happened :-)

2.png

Since the units here are V I would lean towards thinking that the main and sub sensor voltages are "raw". So it seems like something is killing that signal after 10 mins.

One thing to maybe check next, is to measure that conductor as close to the ECU as possible. Measure it when you know the car is NOT in limp mode, while datalogging, and see that your volt meter measurements match what the ECO sees. Then go drive it, let it go into limp, then take it back into your garage but don't turn it off. Presumably, the ECU will still be claiming to see 0V there. Check and see if it's actually 0V, or if you have the same behavior as you did when you checked it before limp mode on the volt meter. That'd at least help it isolate it to either something between the throttle and ECU, or something in the ECU itself (or another signal it's getting)

Or, maybe I just have no understanding of how the ECU works, and it's just pretending the sensor doesn't exist after it's seen something funky. That could make sense, if it's determined it can't trust data from that sensor it could just be shutting it off. In that case, try doing something to intentionally disconnect that line from the ECU, then reconnect it, all while it's running and datalogging. See if you see it go to 0V in the logs and stay there, or if it goes to 0V then comes back to life.

If you had an intermittent short/break I would expect to see that signal bounce between something "real" and 0V. Seeing it randomly jump to 0V and just stay there for the rest of the drive is strange.

[lpmagruder]

EDIT: Nevermind, looks like you did look into this earlier, sorry!


Here's another thought - and I'm sorry if someone mentioned this already (did a quick scan of the thread and didn't see)

At the beginning of the thread you mentioned O2 sensor codes along with intake air (this is measured at the air flow sensor), among others. These have in common a junction at the "joint connector" and go to ECU pin B30:

3.png

I'm not sure what that junction actually looks like, but it's a place where a bunch of wires are presumably crimped together so there's some likelihood for something going wrong there. If something there shorts or does something it shouldn't, then all those sensors would see an issue.

[Ajzride]

Log the Open/Closed loop fueling status and see if limp mode corresponds to the switch from open to closed.

[lpmagruder]

Sorry for all the posts - I should just be collecting my thoughts into one post.

Last thing I'm seeing, is I keep running into the test mode connector when I trace from the secondary sensors you mentioned. I think test mode status is a field you can select when logging. May be worth throwing into your log parameter list and see if it's kicking on.

From this page; most of your original codes are there (minus the throttle stuff): https://iwireusa.com/blogs/iwire-uni...baru-test-mode

[lpmagruder]

Log the Open/Closed loop fueling status and see if limp mode corresponds to the switch from open to closed.

It "should" be in closed loop off boost, low engine load, low throttle angle, at least that's how it was on my 03 when I was tuning. When his car went into limp mode his manifold was in vacuum, 2300 rpm, ~10% throttle angle.

Though, that got me looking at the O2 sensor he logged. I didn't notice initially but he logged the rear, not the front which is used for closed loop fueling. Is anyone here actually running the rear sensor? I'm just running the first one and was under the impression that the rear was only used for cat efficiency checking. That signal seems to be jumping from 0V to ~1V without much correlation to what the car's actually doing.

And when it's at 0, it's pegged at 0, not bouncing around a small voltage. Again, I've never logged or looked at this sensor to know what it should be doing, so there may be nothing here too.

Attachment 190136

It's a little late to fire mine up tonight, trying to stay in the neighbor's good graces. But I can try logging tomorrow and see what my (unconnected) rear sensor is logging like if you think that'd be useful.

[FFRWRX]

This is all really good stuff!

So I just pulled up your logs. My initial takeaway is that as soon as your main throttle position sensor loses voltage, the sub sensor voltage spikes. Maybe this was just you actually mashing the throttle since it went into limp mode, so maybe this is nothing.

One thing to maybe check next, is to measure that conductor as close to the ECU as possible...

In that case, try doing something to intentionally disconnect that line from the ECU, then reconnect it, all while it's running and datalogging. See if you see it go to 0V in the logs and stay there, or if it goes to 0V then comes back to life.

I didn't notice the sub sensor voltage going crazy when in limp mode, but you are right. I don't remember flooring it as soon as it happened; I could have, but don't think so. I'll see about measuring the actual voltage at the ECU since I did wonder if what is showing (0 volts) is real.

Log the Open/Closed loop fueling status and see if limp mode corresponds to the switch from open to closed.

Can't find that in the data logging parameters. Maybe I just don't know what it is called.

Last thing I'm seeing, is I keep running into the test mode connector when I trace from the secondary sensors you mentioned. I think test mode status is a field you can select when logging. May be worth throwing into your log parameter list and see if it's kicking on.

From this page; most of your original codes are there (minus the throttle stuff): https://iwireusa.com/blogs/iwire-uni...baru-test-mode

I saw a post somewhere that showed most of the codes I get when in limp mode. I thought at one point that maybe the test connector wires were connecting somewhere. I did disconnect them from the ECU and went for a drive and it still went into limp mode. But maybe something related to that.

I don't see that the test mode connector is a parameter to log...would be great if it was.

Though, that got me looking at the O2 sensor he logged. I didn't notice initially but he logged the rear, not the front which is used for closed loop fueling. Is anyone here actually running the rear sensor? I'm just running the first one and was under the impression that the rear was only used for cat efficiency checking. That signal seems to be jumping from 0V to ~1V without much correlation to what the car's actually doing.

Yes, pretty sure the rear sensor is just for checking the cat, so maybe no point in logging it. But I did log the front one:

Screenshot 2023-09-16 at 1.18.19 PM.jpg

But you are right, it didn't actually log those. Next time I'll check the screen to see if they are being recorded before I take off. I did read somewhere that some people had an issue where the front O2 sensor wasn't working, but didn't show an error code, but the car did go into limp mode. So I unplugged it the other day and went for a drive to see if it made any difference. It didn't. I did plug it back in but I'll give the connector a shot of Dioxit to make sure the connection is good.

This is all good stuff. I'll report back after doing more checking/driving/logging. May be a couple days. There is a British car show I want to go to tomorrow (the largest one in North America). No, not taking the 818 even though it has the reliability of a British car right now. I've got a Tiger I want to make sure is ready for the trip; no ECU, no power anything, nothing to data log, almost boring.

Rick

[lpmagruder]

For what it's worth I just drove around a bit monitoring (forgot to actually hit the log button) my (deleted) rear o2 sensor, and it's flat lined at 0V. If you like most are not running the rear sensor and it's seeing that voltage fluctuations, may mean something.

[FFRWRX]

I am running the rear sensor as well as the front. I could unplug the rear one and see what that does. It shouldn’t do anything, but who knows.

[FFRWRX]

I'm really at a loss now.

I measured the voltages for the drive-by-wire pedal. They were all good.

The pedal connector (not connected, but ignition on) gave .68V-3.3V, pedal not pressed to pedal floored. Normal is supposed to be less than 4.8V. This is from connector B315 pin #4 to ground and pin #1 to ground.

Measured at the ECU (pedal connected, ignition on) pretty much the same numbers, measuring B135 pin #23 to ground and pin #31 to ground.

The above voltages are lower than the max "normal" of 5.5V for the first one and 4.8V for the second one. Are mine too low?

I can't data log the front O2 sensor. Romraider has it listed when I choose what to data log, but as soon as I turn the ignition on, they are no longer available:

Ignition off:

Screenshot 2023-09-22 at 6.21.11 PM.jpg

Ignition on:

Screenshot 2023-09-22 at 6.21.22 PM.jpg

I have read on-line about this happening. There didn't seem to be a reason other than the data log definition doesn't allow it for some reason.

I decided to go for a drive and data log again. I did unplug the rear O2 sensor. The car went into limp mode faster this time. Maybe because I had it idling for longer before driving off. The last time the "Main Accelerator Sensor" voltage went to 0 when it went into limp mode. This time that did not happen. So there was really no change in the data logging when it happened. The only way I can see that it happened is that the Accelerator Pedal Angle maxes out at 9.02 when in limp mode, just like last time.

I put this latest log in Dropbox if anyone wants to see it.

Data log from today:

https://www.dropbox.com/scl/fi/httj9...z82j6dbts&dl=0

I'm really at a loss now as to what is going on. The car is basically not drivable as-is (not fun getting back home in limp mode). And everything I test checks out fine. The only thing is that the max pedal voltages are maybe a bit low; testing at 3.3V max compared with an allowable of well over 4 volts. Anyone measure theirs as a comparison? I don't know what the next step is since everything keeps checking out fine.

Rick

[Ajzride]

Have you tried just letting it idle in the driveway for an hour to see if it hits limp mode while not moving? And perhaps doing that twice to see if there is some correlation (engine temp, AFR, etc)?