Help! 2021 4Runner won’t start!

First time post here! Unfortunately it has to be a help post.


I have a 2021 4Runner that will not start. It cranks just fine just will not fire up. my battery has 12.91v. So I know I’m getting plenty of juice and my battery isn’t dead. I am also getting a smart key system malfunction message.


I have aftermarket lights and electrical mods however NONE of my lighting or electrical taps into the the factory wiring. I have used fuse taps only for my switch pro and that’s it.


Backstory: my check engine light came on last week. I took it to the dealer and they told me that it threw code P2716. They told me everything looked ok and cleared the code. They did not know why the code was activated.


Two days later I’m driving to work. I’m traveling at approx 70mph on the freeway when I feel almost like a stutter. It would do it multiple times between approx 1700-2000rpms. No check engine light.


At this point out i know something isn’t right. I continue my drive to work with intentions of taking the truck into the dealer the following day.


When I went to leave work my truck would not start at all. It cranked, but would not turn over.


I had it towed to the dealer and the Dealer claims whatever the issue is they can’t fix it and it’s related to the electrical mods. I call BS. They want me to pay 650.00 just for them to diagnose and maybe figure out the problem.


I have approximately 11k miles on my truck and have had no new mods installed for a while.


I was told by the dealer that I would have to pull out ALL modifications if I want them to look at it under warranty. I’m a little frustrated because I know this doesn’t have anything to do with the aftermarket mods.


I’m having the vehicle towed back to my house tomorrow to try and trouble shoot myself and maybe take it to another dealer.


Anyone have any insight?


I apologize for the long winded post.

 

I think a little more info on what “electrical mods” you have done could clarify this a little. Our trucks involve a highly incorporated and complex electrical system. Believe it or not, even malfunctioning bulbs can cause some significant problems. I’d say the dealership isn’t necessarily wrong by asking you to return it to stock to solve an electrical issue after electrical modifications.

That said, I had a fuse blow the other day and it didn’t even look blown. I replaced it and that seems to have fixed the problem. May want to start by checking your fuses

 

Maybe your electrical mods have nothing do with it but it seems likely that they might and I can completely see why the dealer is taking this approach. This is one of the reasons I don't want to mess with anything like this.

 

Check the fuses, check for ignition spark, check fuel pressure, injector pulse & check for codes.

 

if its showing a key malfunction is the engine immobilizer stopping it from firing? I would remove the mods and see what the dealer says.

 

Wish you the best in figuring it out. After reading this I will have dealer do any work I need then it’s on them if something goes wrong.

 

Maybe chewed wiring harnesses from rats or mice. Do a visual inspection.

 

Could be anything really. All you need is fuel, spark and air.

 

I read a long detailed post on a Tacoma form a few years back (2016 or 2017, I think) of a guy how spent THOUSANDS to have "fuel" problems fixed on a brand new Tacoma because they told him it was caused by his off-roading (claimed he got sand or dirt in his gasoline - he swore that never happened). Twice his Taco would not start after a day of off-roading then washing it.

Someone on the forum noticed in his forum signature page that he had put in aftermarket halogen headlights. They highly recommended that he reverse that mod and see what happened... he did and it fixed the issue. Apparently, everything is somehow tied to the computer in a way that if you alter the current draw enough (added lights, changing wiring of some kind that increase the draw... it can cause issues when if a little water adds to the problem (damp unsealed connectors perhaps?)... there is not enough current for the computer to "see" the proper levels on some sensors an it shuts things down.

In his case, it caused the fuel system to stop sending fuel to the engine. Turns out that somehow, a connector or something was allowing a small amount of water (or just moisture?) to create a problem where the light were drawing much more current than stock. So when he washed his Tacoma after each off-roading event, it would not start again. All the codes pointed to fuel system failure. The dealer replaced his entire fuel system twice - neither time would the warranty cover it, and it was north of $10K each time, if I remember correctly. He put his original lights back in, and never had the issue another time. Weird, I know, but that story sticks in my mind every time I consider mods... I always think about how it might impact the overall system in these new super-smart vehicles.

Definitely NOT saying this is your issue, but take care in saying that the "mods" may not be the cause. If it's pulling current from other loads, it could potentially be ONE of the reasons. Enough of a reason that it makes manufacturers always point the finger toward those items as culprits.

 

jm2c Lift the positive and negative wires to whatever mods you have made and see if that corrects the issue. It's not at all uncommon for aftermarket electrical parts to be bad at the time of installation, or go belly up after miles of use, and that's something 'Nanny' will not tolerate.

 

When I first started reading your post I thought it might be your key and was gonna suggest trying a different key because of the immobilizer system. But you probably have the keyless setup.

I would have to agree with the others, I would try undoing your electrical mods even though you are confident it’s unrelated.

My boy had aftermarket LED turn signals, and their drive circuit went bad, so when he applied the brake, the dome light would come on rather than the brake lights. And yes they were totally unrelated?

This is exactly why, I will not do electrical mod’s to a modern car.

Best wishes with your troubleshooting and repair.
Let us know how it turns out.

 

Did I miss what the code was about? Maybe that’s a clue.

I guess I agree, go through your work, and undo it, even if temporarily to see how it responds. If you have aftermarket lights of any sort, switch it back….

Kinda sucks, but you did the work once, so the second time should be faster.

The key would be a simple answer, because Ive seen cars crank all day long and not start due to key modifications. Any key modifications? Have you tried your second key?

Also, list out your electrical mods, many heads are better than one at brainstorming…probably anyway lol

 

Regarding the key. I remember years ago, I had a rental car and noticed there was a valet in the glove box. I tried starting the car with the valet key and it would crank the starter but the engine would not start.

I panicked briefly, then tried the original key that they gave me and the car started right up.

Apparently the valet key was never programmed to the car.

This probably isn’t your issue but I thought I’d share my story with others.

 

P2716 TOYOTA Code - Pressure Control Solenoid 'D' Electrical Shift Solenoid Valve SLT

https://www.engine-codes.com/p2716_toyota.html#

 

I had a 12volt phone charger cause issues on my 2018 tacoma, stealership couldn't figure it out, basically it would cause my dash to blink and black out, turned out the phone charger was sending ingress back into the electrical system only way I figured it out was the rental camry they gave me did the same thing when I plugged in the charger. Stealership tried to blame the alarm system they installed and wanted to charge 600 to remove it of course

 

I remember this thread. The dealer kept saying the sand was killing it or some shit right?

 

Google fu...

"Error Code P2716 is defined as Pressure Control Solenoid 'D' Electrical Shift Solenoid Valve SLT. This suggests an anomaly in specific electronic pressure control solenoid or solenoid circuit. This error code is a manufacturer-specific trouble code, meaning it does not apply to all vehicles makes."

Seems like something is interfering with the circuit, which supports the problem coming from an electrical issue. If I were OP, I'd save the $650 diagnostic fee, disconnect my modifications, and return it to stock configuration to see if that fixes the issue.

Me too, guy was a military medic from what I remember. They kept telling him it was sand in his fuel system...

 

Thanks for all the replies!

I have Baja designs light installed for camping. Ditch lights, and scene lighting 8 lights in total. All of these go to the switch pros panel.

I just picked it up from the dealer to trouble shoot on my own. Dealer note say that the smart key system states “immobilizer”. I’m assuming it was activated somehow. I’ll be checking for cut wires and removing the electrical components. Aside from that not much more I can do.

 

You tried your extra key yet?

 

yes I tried both keys.

 

Very frustrating for sure. At least you weren’t out in the boonies.

Electrical gremlins can be difficult to pin down.

 

It does sound like a pretty simple set of mods. Should be easy to isolate the switch pros panel.

edit: I would be very suspicious of the fuse tap first, and the actual switch pro second

 

Can you clarify how how the switch pro panel is powered? (I dont want to assume anything.)

if power is solely through the fuse box (through the tap), there is potential that the fuse tap passed too much current and didnt blow when it should have? Im spitballing here. Go through that fuse box, heck all all the fuseboxes, and check each fuse. This is after you replace the tap fused with a stock one.

 

So a little update. I got it home. Pulled the negative battery cable and let it sit for 15 mins. Connected the cable again and it fired right up. I’m curious what enabled the immobilizer.

 

I paid 155 at the dealer. Should I be upset that they couldn’t do something this simple to trouble shoot the issue?

 

not if the problem is intermittent, chasing intermittent electrical issues sucks

 

Yes! Even when he went rock climbing on the next outing!

 

unplugging the battery for a bit is like the "reimage" process in the computer world. almost.

 

Has anyone had issues with their smart key System? I know my keys suck at locking and unlocking the truck. I have to pretty much be right next to the vehicle in order for it to work.

I have had a message pop up saying key not detected even when the key is in the vehicle.

I think it could be an issue with that.

 

This person posted my exact symptoms. Idk if his vehicle is modded or what the actual outcome was since he never posted a resolution.