Lexus C/OPN Relay issue.
 

2006 Lexus GX470.
Looking for advice here. I had to remove my intake to do work under the intake, also installed new injectors and plugs. Had the batt disco'd for days. Put everything back and the ECU will not ground the C/OPN relay coil so the C/OPN relay can supply +V to fuel pump relay. Everything else seems ok (voltage is there at C/OPN relay, pump works, no DTC's, all fuses are good, etc etc). The ECU pin that controls the C/OPN relay coil is the "FC" pin on ECU (common collector transistor most likely). From the wiring diagrams the "FC" wire between ECU and C/OPN relay appears to be a homerun wire, which makes sense from a safety perspective.


I found this post in this forum. Dealer told him "some connectors". What connectors could it be? Could it also be the immobilizer? Not much info about what the immobilizer does. Does it serve as a security feature and safety feature if say an airbag is deployed, cutting off the C/OPN relay?

http://forums.pelicanparts.com/off-topic-discussions/646599-mechanics-need-help-understanding-toyota-fuel-pump-problem.html

Well, after a bunch of testing it seems my fuel pump went south. The ECM, relays, fuses, sensors, all seem to be ok.

I suspect, when the fuel rails and lines there went empty and was just air after install, when the pump cam on it has no liquid resistance and probably took a dump. I can run the pump manually and some fuel come out of the fuel line, but it's not 50psi. It also sound funny when the pump is running. I am now in a project to replace the pump. But get this, there's a access panel under rear carpet BUT NOT BIG ENOUGH TO REMOVE PUMP THROUGH! Yeah, I am not dropping the tank, just gonna cut open what's needed and TIG it back into place.

With Toyota, the ECM code will not engage C/OPN relay until the ECM gets the START (starting) signal AND signal from crank sensor. Once the engine is running (I assume a rpm threshold) the ECM will keep C/OPN relay energized, which feeds the pump selector relay, etc.

And just to note, I am not mechanic by trade, I just a DIY'er with a lot of tools ;)

So you are going to TIG weld right above the gas tank and the fuel pump. I would suggest you do that outside and have a fire extinguisher close by and an assistant to put you and the car out if it catches on fire.

Ill second the bad idea. You will have residual fuel everywhere, and fumes . Can you loosen, and lower the tank just far enough to wiggle the pump out ?
I have a few buddies who have caught cars on fire. You will have saved no time if you burn your garage down. In this situation, you will be in the car, right smack on top of the fuel tank , with no way to escape when the fireball comes at you . Don't be a crispy critter

I understand your concerns. There will not be fuel and fumes. Once the pump is replaced it's basically sealed up. I can then do a mild wash down of the area. The top of the tank in that area will get covered with welding blanket. I will probably just opt to do some TIG spots as needed (1 per inch, etc) and then seal up the rest. Or I might flange the cutout piece, butyl rubber under the flange, stick it, then just tack flange to body in a few places to hold it (making it ez for another entrance in the future). The original access panel will remain, etc.

I am a pro TIG'er ;)

No, there is no way to drop the tank just a bit. There a bunch of hoses and connectors that need to be undone, then the tank has to be taken out completely.

Took just 40min to get to the access panel under the carpet (me going slow and took both seats out, etc). Why Toyota did not make a real FP Replacement access panel is beyond words.

Yes, I have fire extinguisher, but I don't think it will be used :)

Here's the prep & cut. Used a fine tooth blade, and had to drill out 3 spot welds. I did manage to break a clip that cannot be replaced on it's own, but I will deal with that. Notice how the cut on right is far enough back that it's in the hat channel so I did not need to cut the edge of the hat channel off. This looks like enough room, but if needed I can trim the edge of the hat channel.

I am waiting on some parts and ring tool to finish the pump swap, but going back to TIG'ing it, I think for safety reasons I will TIG the seams 100% and then TIG tack back where the spot welds were. Then will clean/prime the area (underneath I can reach with my hand, so maybe a wipe of some sort to protect the metal) and then just a quick shot of white spray. Like it never happened ;)

https://i.postimg.cc/26S1DhbQ/cut1.png
https://i.postimg.cc/fWFJG3wd/cut2.png

It would not worry me to tig weld that.

Does it even need need to go back in?

I do hwy driving. A at-speed crash or rollover could cause the plastic tank to rupture or lines to rip off, don't want fuel easily spilling inside the vehicle.

So for shear safety reasons I will completely TIG it back like it never happened, etc.

I just did not want to muck around with hoses/clips/connectors of dropping the tank. This is a 14.5yr old vehicle and it's showing signs of dry-rot on plastics and stuff, more so outside than inside. So to avoid that headache I went this route, etc.

And while I have the carpet up, will add some 50mil sound deadening mat to make this boat a tad more quieter inside.

You could just weld tabs on the part you cut out and fasten it back with short screws, that way you can remove it easily next time.

Well, I thought about it, but then reality sinks in.

The OEM pump/filter went 14.5yrs and 225kmi. The new parts should last as long or longer. I am not likely to have this vehicle another 14yrs and the engine most likely won't make another 225kmi w/o needing major rebuild.

So, I believe this is a 1-time thing, thus I will just close it back up like it never happened, etc.

Just be sure to get a OEM pump from Lexus and not some garbage cheap pump made in China.

A lot of the Denso stuff is MIC.
I am installing a URD pump kit (USA Walbro pump with an additional external filter).

Today I prepped the metal edges for TIG work to be done. Just waiting on pump kit and ring tool to arrive.


https://i.postimg.cc/c4r1S1fz/prep1.png
https://i.postimg.cc/vBYMSGQ3/prep2.png

I hate that when they give you an access panel, and the thing does not fit through the hole anyway. What is the point even?
I have run into this with SAAB, Audi, and I think I remember a Toyota getting me before .
Its kind of like :http://forums.pelicanparts.com/uploa...1602177544.jpg
Be careful either way, you will spill some fuel

PDF of the Lexus C/OPN
https://www.clublexus.com/forums/gx-1st-gen-2004-2009/954167-that-tricky-c-opn-relay.html

Prius info on the relay. Not the same thing but a good discussion.
https://priuschat.com/threads/need-to-know-where-the-c-opn-relay-is-with-image-if-possible.153355/#:~:text=C%2FOPN%20relay%20is%20part%20of%20the%20 integrated%20relay,but%20not%20start%20%28Prius%20 cranking%20sound%20like%20running%29.

posts #13 & #14.

TY for that.

Yeah, I read all about the C/OPN relay (that's my thread on Clublexus, etc), I studied vehicle wiring diagrams. What's hard to find is how the ECU uses input data to know how outputs will work. I have it all down now, and all seems ok there.

Yeah, a little fuel might spill, but the interior floor will have plastic over it, and any that gets on the tank will be washed out later. I am not really concerned here.

Update:
Good news, pump canister made it out w/o additional cutting. My initial guesstimate at the opening size was just enough.

The float sending module looks like toast, so a new one will go in.

The new pump is a Deatschwerks 255 lph unit.

And for those needing to splice wires in the tank, I offset the cuts (so the two wires can't touch each other), do a linear twist if the wires can be soldered (see note below), solder it, and then use Kynar (or the like) PVDF or FEP heat shrink tubing over each joint (slip tubing on 1st, etc, McMaster, I chose PVDF )

Note: some OEM's use wire that have coated strands of copper which cannot be soldered, or just not copper wire at all. In these cases crimp the wire ends into a barrel connection, then fill heat side with solder iron, put some solder into barrel, etc. If you scrape the wire strands carefully with a razor and see copper underneath, then try and scrape some to expose some copper, crimp then solder, etc.

Sadly, new pump did not resolve the issue.
I will run some TechStream diag to see where that takes me.
I am still leaning on fuel delivery issue.

^Whaaaaaa?^^^^^ all that and same problem? Man...…..

Yep.

At least it now has a better fuel pump and a new fuel level sending unit ;)

My Techstream finds nothing wrong. I wonder if the 'new' fuel injectors are stuck closed (not very likely, they had just come from being serviced), or maybe a bad cam sensor? The no-start sounds like bad timing by ECU.

Fuel tank was filled up past 3/4. Maybe the return valve on the fuel rail is goofed not allowing pressure to build? Techstream does not seem to have a Fuel PSI monitor.

Frustrated at this point.

https://vimeo.com/465191913

My bet is the immobilizer. You could have lost the program when the battery was out of the car. You will know if it has lost the program if the key illumination on the dash when the key is in the ignition II position is not lit up. Try placing the fob right next to the push button start then press and see if she fires up. The battery in the fob might be dead, and that procedure is a fail safe way of starting the vehicle when that small little battery dies.

You can try this too.

https://forum.ih8mud.com/threads/efi-relay-bypass-kit-immobilizer-fix-for-uzj100-lx470.952811/

Well, I went there initially, but Techstream is showing no activation for immobilizer, and the dash light for security/key is not illuminated when I turn Ign to run/on position. The key batt is not required for the RFID Ign ring to detect a keycode from the key. Key batt is only for the Rf lock/unlock/panic buttons on key.

I am kinda stumped at the moment. Tomorrow I will attempt to verify spark and Injector pulse and injector working.

Is it cranking over and over and over, or cranks fires and dies, or no crank at all?

That was an interesting read which I only skimmed.
-It looked like if the light comes on for three seconds and goes off with normal self test, the immobilizer is okay and something else in the ignition/cranking/fuel system is wrong.
-If the light comes on and stays on after three seconds it's a bunk immobilizer. (but I may have read it incorrectly)

You might want to start isolating:
Get a spark plug tester or inductive pickup or perhaps use OBD2 tester to look at firing line and see if there is actual spark or big pulse. It could be as simple as a bad coil.

Get a Noid light for the fuel injector. If it flashes while cranking, the cam/crank sensor and ecu is telling the fuel injector to fire. Those are 'probably' good. That cuts the problem in half.

If electronics and spark is good go on to fuel. Should be able to test line pressure off the schrader valve on the rail if equipped. See if there is bleedoff/leakdown after 5min which indicates leaking injectors or bad check valve. A plugged filter or pickup screen perhaps will cause low delivery pressure.

There's a vid a few posts back, post #19.

This vehicle has a auto crank, when the key hits that start position you can let go of the key (it sprngs back to run/on location), ECM then attempts to start, and will stop cranking if no start within a few sec (5 or 6 , etc) to save starter and batt, etc.

The coil packs should be fine, they all working when I did initial work. I did however install new NGK plugs. Maybe all the plugs are bad, will check him with Noid light.

So, Toyota in their great non-wisdom did not provide a test port or even a fuel pressure gauge/sensor. To test you need a SST and connect it by removing a banjo bolt, which requires use of new washer gasketes for the test, and new washer gaskets after removing the tool. As dumb as it comes.

The front of the fuel rails have a bolt in where the initial CNC is done to bore the rail. I will see if I can adapt a sending sensor there so I can just hook up a gauge when needed.

The fuel pump is a-ok (its new). But I cannot see if the fuel pressure regulator is goofy or not, wont be able to know until a pressure test is completed.

The CAM sensor though has me baffled too. Take a look at this:

If I disconnect the cam sensor connector (right behind the radiator hose) and try to start it, ECM does not throw a DTC. <---- odd.

But, OEM wiring diagram shows it a bit different. The diagram shows only two wires sensor side. So what's that 3rd wire for?

HARNESS (female pin connector)
red--------green----green-black
|................|................|
white-----green--------red
SENSOR (male pin connector, the bottom connector in the sensor pic which connects to harness)

Using ohm meter (quality Southwire DVM, I also have a Fluke, etc) on sensor pins only (switching meter leads on every pin set, etc). Is this a good or bad sensor? Maybe its a powered Hall sensor and not a simple 2-wire coil pickup? "green" below is more like a darker green, etc.

White+ Green- = 0ohm
White- Green+ = 754ohm
Green+ Red- = 451ohm
Green- Red+ = 1126ohm
White+ Red- = 0ohm
White- Red+ = 1892ohm

https://i.postimg.cc/FHx3Zbnq/cam-sensor.png

https://i.postimg.cc/yxqDBWbc/cam-sensor-pic.png

(apologies for having forgotten most of my book learning from 20 years ago. layman here. I'm just throwing spaghetti at the wall.)

Aren't there:
1. pulse type (piezoelectric)
2. hall- effect (magnet transfer) minimum 2 wires could be 3 i think.
3. blade-interuptor (magnet or light/laser) minimum 3 wires

per the first diagram:
I'm guessing that's a powered Hall and white/black is power in a loop off the ECU. Probably 5-9volts.

NCA/BRN leads to J/C 26 and then to "EG" ground. That could be the signal output.
The second pic shows a red wire. But you have a green wire...
Is that the immobilizer?

The J/C 26 is a ground plane (shield) around the sensor. Well, it's shown like that in the schematic. You also notice in the 2nd pic that a bare wire comes out of the wire bundle and is crimped to the metal housing. I think this too is also a shield wire that only shields that extension wire between harness and sensor, etc.

The 2nd pic is not immobilizer, it is the CAM sensor in it's holder/mount with the extension wire. The extension passes through a rubber grommet in the upper plastic cam gear cover, where it then connects to the harness connector.

Skip my Q about the cam sensor.

Little not-so-known fact, Toyota made two gen's of GX's for NA market, the GX470 (2UZ-FE) 2003-2009 then came the GX460 (1UR-FE) in 2010.

Here's the deal though, 1st gen got some major changes in 2005, including dual vvt-i. Along with that the types of sensors changed to.

2003-2004 , then major changes in 2005, yet they still call the 2003-2009 the "1st gen GX470's". In my opinion 2003 to present is three gen's of GX's.

So, what does it all mean? It means the wiring diagram I was looking at is for the 2003-2004 GX's, those vehicles use 2-wire cam sensors !

Lesson learned.

A good OBD2 scanner will tell you if the cam sensor is pulsing when cranked. (plus everything else of course)
You need to find if it's sending a signal.

Not sure if a DVOM will do it right off the sensor but it's worth a try.

One of my auto tech profs talked about back-probing sensors while attached:
Run a thin needle through the insulation and alligator clip off of that. Check with Ohm meter first for connection.
A drop of liquid electrical tape will seal it back up.

I have the Techstream software, but I don't see any live data for cam sensor. The service doc shows to probe the G wires at the ECU with a scope.
I have a batt powered bench scope, I am setting up to probe it.

Got the cut mess all back together, even wiped the weld area underneath with an epoxy to help prevent rusting.
Then added some KilMat under the feet and seats.

https://i.postimg.cc/dVxD5T4F/fuel1t.png
https://i.postimg.cc/vThZf1cp/fuel2.png
https://i.postimg.cc/Jntsxzcv/kilmat.png

I put my scope on the cam sensor signal wires (G2+ and G2-) but do not see any recognizable signal, yet my Noid light on #5 did light up 3x during cranking. 3x on Noid means the crank would have had to go 3x 720deg (6 full crank rotations), but I don't think it cranks that long. Odd.

Have you checked the EFI relay? If my 1991 Cruiser won't start, it's the first thing I check.

I think I have checked relays and fuses like 6x already. The vehicle was working 100% before any work started.
The work done was to do some simple maintenance to the 2nd air pump crap that's under the intake. At that time I had to clean out the intake because it had oil from PCV laying in bottom of intake, I then replaced the fuel injectors, and installed new plugs.

The 'new' injectors came from a 2007 107kmi 2UZ-FE Tundra wreck (ebay), they are OEM injectors, I then sent them to RC F.I. in CA to be serviced. The report shows they were fairly bad, but after service the report shows them good & matched.

I will now go probe some injectors, check ohms, hear them click open, probe the wires to make sure they are getting turned on.

I made some break-out patch wires so I could probe cam sensor w/o stabbing the wires.
https://i.postimg.cc/7LVWsg86/camwires.png

cam sensor appears to be ok.
https://vimeo.com/470649421

Fuel injectors appear to be stuck closed. Not sure why, have to call RC.

You sure you have not pinched a wire, or juxtaposed a few connectors when you had the plenum off? It happens to the best of us sometimes.
You need to be looking for batt+ at the injector, then look for pulsing ground at the other side of the injector . Follow the ground back to the ecm, or follow the hot side back to the fuse box, or whatever relay powers them up . If you apply power and ground to an injector, it should make an audible click.

I need to say this, please dont take offense. You are way down a rabbit hole at this point. Something's changed since the initial work. As Fred has asked, something pinched or connected/ cross-connected. You may ( have created) a CAN bus problem when reassembling through human error.

It's odd the car sat for a few days and the battery died. In that situation the battery may be in an extreme low state of charge- it appears dead but still has residual voltage so all capacitor memory remains.

We've all been there. All of us that do problem solving whether it be mechanical or say, mathematical go off path. It's hard to get out of that. From your posts it seems to me some basic testing by eliminating ( with absolute certainty) has been guessed or not completely ruled 'yes' or 'no'.

Have you considered a second opinion by expert diagnostic guy with a Pico scope?

Solved
 

6 of 8 injectors were stuck closed ;)
I bumped them with 30v from my benchtop power supply to un-stick them.

I spoke to RC tech support, this sheet happens from time to time. Nothing to worry about after they un-stick.

Problem solved.

My batt never died ;), it was on a Minn Kota the whole time. I took neg terminal off batt for a few days.
Pico scope? I have portable (batt power) benchtop scope, but it no Pico ;) , post #33 ;)

I always consult with 3 people,....... me-myself-and-I ;)

I checked out some of the the Pico Scope videos and it is awesome.

$1,000++ is a big price tag but that investment works out over time for those who wrench at home.
Their website, documentation, and interface features could use a few more user-friendly tweaks, but it looks to be a powerful tool still.

Find the source of road vibration. Find electric component flaws. Find relative compression. All with hooking up a few sensors and running some tests. No throwing a pile of parts at an unknown problem. And clean hands stay clean.

You notice in the video he points out problems such as the starter motor probably skipping a beat, and the #1 cylinder having over-spec compression and possible causes.
-This is not pointed-out by the software itself and there is some theory applied there which requires mechanical experience.
-All of those could be added as pop-up warnings or highlighted by the software as readings out of normal.
-The entire program routine could be customized by selecting from a simple job menu at the very start and graphs/scales are preset for easy reading.
-The job menu could have stock pictures for which sensors to use and where to attach them. It could even go deeper into standards for each model of vehicle.
-With all 4 sensors attached, it could run multiple diagnostics automatically all at the same time.
-Even better hypothetically would be plugging only one simple plug into the 16-pin OBD2 port and getting it all, but I think the refresh rate on those are too low for these tests.

<iframe width="560" height="315" src="https://www.youtube.com/embed/LEzkoF-gAn4" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

If you have the time to sit in on discussions by the pros..."Trained by Techs" is also a channel worth watching:
https://www.youtube.com/channel/UC6pKbmHz16uocON8ZZTj44w

Agreed, a shop needs a Pico or MicSig. But I no shop ;)
My tools can do all the measuring, I do all the thinking.

But duly noted, I no see where a Pico can tell you that you have a stuck-closed fuel injector. I made a test cable (cause I have extra toyota-denso style injector connectors) and started on #5 to see ohms, that looked good, then I did the batt test, no clicky. Ut-o, is it really stuck? Made call to the place that serviced the injectors, got info, bumped them with voltage higher than batt, just kept bumping the 1st one in +1v increments until it popped loose, about 28v seemed to work, just went around the horn using 30v. Vehicle runs great.

Lessons learned, and new fresh parts installed. Overall, me just tired & happy ;)
Geez, even found that the valve covers were 120ohms to body ground! Why? I dunno, but the covers had nice free threaded hole on them, so now they are zero ohms to batt-.

http://forums.pelicanparts.com/suppo...s/beerchug.gifhttp://forums.pelicanparts.com/suppo...s/beerchug.gif

[insert cheers emoji times infinity]
Well done sir.