2nd gen fuel pump troubles

My truck died, seems to be the fuel pump. It's a 4.0l 6peed in an 06. can anyone share how to diagnose one of these trucks? I've heard you can jump 12v+ power directly to the fuel pump via the obdII port, but I'm having trouble finding a pin out diagram for the odbIi port. Can anyone tell me what colour the wire is, or any other ways to find out what's wrong ? Thanks in advance

 

I would not be putting 12 VDC to the OBD2 connector, you very well could fry the ECU.

I would just install a pressure gauge to the fuel rail and try and crank the engine and get a pressure reading.

 

Just turn the key on and listen for the sound. Two people would make it easier.

 

True....one person back by the bed with ear near the fill port. The other person in the cab who turns the key.

 

That was the first thing I did on the side of the road, listen to the gas filler while someone turns the key. Nothing. Then I found out these fuel pumps only run when the truck is cranking or running, I still can't hear it when the trucks turning over. There's snow on the ground here, I crawled under to take a photo of the fuel line connections to see if I can find the tool, I don't know how to split them. I can't see much electrical, it's above the tank. I'd like to rule out the relay first considering the pump is a $500 part and I'm broke. I was hoping it was a filter but there's no filter except the sock on these trucks. I'll probably pull the box off on Sunday and see what I can figure out for splitting the lines and checking power to the pump, I don't really want to drop the tank in wet muddy snow in a tow yard if I can avoid it, and I've only been able to make it to the truck in the dark until today.

For fuel pressure, I couldn't find a Schraeder valve on the fuel rail. Do I need to pull the plastic engine cover off, or do I need one of those fancy fuel pressure kits with the banjo bolts? I wouldn't just be sparking 12v off of stuff randomly, it's just jumping a wire from the corner of the odbII port to another pin. On the older 3.4 tacomas, that also only energize the fuel pump when the trucks cranking, you can bypass the fuel pump relay by jumping 12v+ (from the corner of the diagnostic port) to a blue/white fuel pump wire (in the obd port) and you can hear the pump turn on without the starter noise. I'm trying to find the wire color, or which pin it is, for the 4.0 trucks, or even if it's possible to do the same thing. I dont know where the fuel pump relay is located on the truck, the only other way I know of to test if the pump is getting power is to drop the tank or lift the box off and stab a test light into the wire. I'd like to find a better way to be sure it's the pump before I spend my day off ripping the truck apart.
Figured this was the place to ask.

 

You can command the fuel pump on or off with a scanner, is this what you are thinking of with the obd2 port?

 

I was hoping to just jump 12v+ from pin 16 to a fuel pump wire with a paper clip or a jumper wire, but the more I read, the more I've changed my mind. The odbII (can/bus) protocol in these newer trucks is way different than 90s tacos.

It would be awesome if I could do it with a scanner... I have access to a nice featured one, I think it's an Innova. I will check the manual to see if I can make it trigger the pump, thanks! I still can't figure out where the FP relay is located on the truck, if I could find it I could just do a jumper wire across the relay pins, and/or test if the relay works when the truck cranks. I can't rip the box off or drop the tank tol tomorrow, and I can't buy a pump assembly locally yet anyway, so I'll keep googling.
Edit- I'm retarded, the fuel pump relay's under the hood in the fuse box- I'll go check it out.

 

Have you beat the tank with a mallet yet? Sounds crazy but I've seen it bring pumps back from the dead.
Obviously the pump would need replaced soon.

 

Same thing with starters and blower motors

 

Put 12v from the battery to the pump wire. Also if your going to replace the pump check rockauto, way cheaper. Denso is OEM Toyota.

 

Thanks for the help guys, I can't believe I didn't even think of beating on the tank! I've seen it work with old beaters but it never crossed my mind to do to my truck.

I got to see the truck in the daylight today, dropping the tank doesn't looks so bad, snow/mud/ice or not. I thought I'd rule out the relay first though, now I'm even more confused. The fuel pump relay doesn't close when the truck cranks, I pried the cover off of it and looked at the contacts while someone turned it over. Fuel pump doesn't turn on if you manually close the contacts, or pull the relay out and close the circuit with a jumper wire. The test light I brought had a dead bulb, but I can say for sure the FP relay isn't closing, I think the problem is somewhere in the circuit before that, no idea what the next step is.
I'm not a mechanic, just a guy that can't afford to pay a mechanic right now, and don't want to pay to tow the truck again. There's also a weird whine under the hood when they keys on I never noticed before. I'm wondering where the signal that triggers the FP relay comes from? Like its it trigger from the ignition start circuit or the starter or MAF or where and how? All of this is way over my head, but I'm without a truck til I figure it out.

 

Your pump is 12 years old ,just replace it and go from there.

 

Why replace what may be a good working part? His pistons are also 12 years old...so I suppose he should rip the block apart.

I second diagnosing the actual bad part.

See if you can command it on with a scan tool. I suppose u ou could also disconnect a fuel line upstream of the pump and see if it sprays fuel when cranking although that could be messy.

 

You are entitled too your opinion,same as I am.

 

Your comparing apples to oranges. Swapping out a fuel pump on these trucks isn't hard. I've done one in about 45 min. Way easier to pull the bed than drop the tank. Another way that I use in the shop is get some throttle body cleaner and spray it in the throttle with the use of a buddy starting the truck and pressing the gas, if it starts with spray you know you have a fuel delivery problem.

 

This has some similar symptoms as what I'm experiencing... '15 Tacoma died while driving. I can get it fired up briefly with starter fluid in the intake. No power to fuel pump relay, jumped c/open and got power to FP relay slot 3, jumped FP relay slots 3 to 5 and nothing happening with the fuel pump, per instructions from a toyota tech.

It threw three throttle position sensor codes (P0121, P0123, P2135). Seems like it should have gone into limp mode, but it just died and stayed dead. Replaced the TB and still got nothing. The FSM for this gen walks through testing and the three culprits/solutions are new TB, fix/replace wiring, or replace ECM. Wiring isn't 100% ruled out, but I've found no evidence of shorts/bad connections so far.

I'm about to have it towed into the dealership because I've been fighting this thing for a week and a half after work in the dark and not getting anywhere.

OP, did you get it resolved?

 

Told you too just replace the fuel pump (simple) and be done with it.

 

Sorry, thought I updated. Took the cover off the relay, it wasn't closing. Was getting 12v while cranking to the rightmost relay leg, and the upper left, and the other relay slots were getting 0.17v which I thought was weird. So power while cranking to the relay, but it wasn't closing.

Replaced the relay, beat on the tank, fired right up. It didn't throw any codes except the catalytic codes that I'm also too cheap to fix. My box was full of stuff and snow/ice, didn't wanna do the pump if I didn't need to, plus I'm poor. I'll probably order a pump from rockauto or eBay as they're 1/3 the price as my local parts store, and my gas gauge is a little iffy sometimes. Thanks for all the help, those that helped! This place is great, but even if I had've pulled my box off in the snow and spent a few hundred bucks, it wouldn't have started. It was the relay, I can't explain why it didn't work to manually close the relay or jumper wire it. I also beat on the tank, but I've put a few full tanks through it now and not even a sputter.

 

would have sucked to replace the pump and still not have it work.. that's the worst feeling, knowing you did all that work, spent all the money and it wasn't the issue.

 

Glad to hear your truck is up and running again! I hope it runs for many a year to come!