2012 Tundra will not start

Hi first time posting here. 2012 Tundra crewmax 4.6 liter
Truck will not start 4lo light is blinking and traction control light stays on when key is on. Have checked fuses all were good. The thing that has confused me some is I plug my code reader in and it doesn’t read computer just gets an error on reader

 

Pull the battery terminal and let the truck completely bleed down the 12v system. Then reconnect and try it again

 

Do you mean no crank or crank no start?

 

I have disconnected battery and let sit all day while I was at work. Had the same problem when battery was reconnected.

 

The motor turns over fine. When it tries to start it is like it smothers out.

 

Battery voltage good?

 

Yes battery turned over truck fine but I also tried with a jump box as well.

 

Ok you said smothers out when it starts I’m almost feeling like your having posible fuel problem can you hear your fuel pump turn on for a few seconds when you cycle the key?

 

Had my mechanic come by and look at it he doesn’t normally work on Toyota but he hooked his snap on computer to it and it wouldn’t communicate with it either. He is thinking something about the security on it has happened but not real sure.

 

Did this situation happened all of a sudden or where you working on the truck and now is a no start? Make sure you check the Main Fuse in the hood fuse box. It’s so hard to diagnose a vehicle over the phone that’s why I’m asking so many questions I can send you any diagnostic information you need

 

Some good diagnostic info their follow that

 

Near Dead Battery?

 

As mentioned above, definitely try a new battery. It may have enough to crank it over, but not enough to start. Electronics can be fussy without proper voltage. Been there.

 

One way to possibly eliminate this as a possibility is to look for the red flashing light in the display by the clock. Without the key in the ignition, it will flash every few seconds. With the key in the ignition, it should stop flashing and remain off. You aren't using a different key are you? Some keys are pretty much for the door/glovebox/tailgate only and don't have a security chip in them. They won't start the vehicle, it'll just sit there and crank.

With the proper key, when you rotate it to the RUN position, you should get additional dash lights as a way of testing that they work, a Check Engine Light is one of them. Also, as it hasn't been mentioned yet, in addition to the fuses under the hood, there are also a few in the cab above the parking brake pedal. Not the easiest to see, but they're there.

Some info on what you may've been doing with the truck prior to this could give hints too.

 

I drove the truck 2 miles to dollar general ran fine no issues. Got in it the next morning to go to work wouldn’t start. Have tried a different key my has no luck. The red light flashes by clock but goes away once key is put in. When the key is turned on the 4lo light blinks and traction control light stays on. Once you turn the motor over and it tries to start the traction control light goes off but 4lo light keeps blinking.

 

That is some strange stuff, particularly the flashing 4lo light. I've only encountered that on my truck when updating the ECU and I'm pretty sure you probably weren't at the dollar store having that done. I guess, when you have the time, if you haven't already, check the in cab fuses just to eliminate them as a possibility.

 

Yeah I have checked all the fuses under hood and under dash

 

That flashing 4lo light really throws me. Outside of seeing it under the circumstances I mentioned before and when actually engaging 4lo, in my mind it shouldn't be happening but is certainly a clue. The security idea could certainly be something to consider, but I've never had to contend with anything like that with my truck.

Have you had any rodent issues before? They do have a penchant for the soy based wiring insulation that Toyota uses. Have you nosed around under the hood looking for nesting materials or droppings? The ECU itself is mounted in the firewall on the engine side of the glove box, tons of wires over there. Look everywhere though, under the fuse box in the engine compartment for example, under the engine cover, in the cabin filter box...

 

Haven’t ever had any rodent issues one cat outside that hunts anything and everything. Not saying it couldn’t be but haven’t found any evidence of any. I have also learned that the 4lo light blinking can mean different things.

 

100%. But I can only relate what I've experienced or read. I'm kinda tapped on ideas at this stage.

 

Did you get it running yet?

 

Not yet.

 

Any luck?