'21 Tacoma OR randomly dying while driving

Hey all.

Had an issue last week where, at low speed, the truck shuddered and died. Could not get it to restart, or it would restart and then immediately die again before moving. A bunch of warning messages came up at the time as well like Smart Entry system error, low oil pressure, etc. Had it towed to a local dealer who eventually said the issue was a loose positive battery terminal which was preventing the battery from charging fully. They gave me a ton of grief about it because I have aftermarket speakers, a subwoofer and two amps. I have had the speakers and amp in for a couple of months already with no issues. The only thing I had done the day before this happened was Katzkin seat cover replacement and they added heated seats at the same time.

Well... I picked up the truck today and it happened again after they said they fixed it. I contacted the service rep and he said sorry to hear it but maybe I should try a bigger battery. So I am trying to figure out if I should just take it to another dealer or try a new battery first. They won't do anything more if they cannot reproduce the issue.

I checked the battery voltage and it reads 12.75 while the car is off. When running, it is reading 13.86.

Would love any advice or if others have had a similar issue. I read about the crankshaft position sensor issues but my truck is a '21 so I thought they had already addressed that.

 

Welcome to the forum. Find another dealership to take it to as yours is just guessing, not troubleshooting.

 

Take that aftermarket shit you got installed out. If it was driving fine before the install, then its something installed causing the issue.

 

Either improper install, and/or they are right and your battery wasn't charging properly. Sounds legit. Time for a new battery and hopefully your install is not the issue, but we'll never know because we can't see it. And I second the notion to check your wiring on the heated seats. Make sure you clean terminals and tighten properly.

If it's not throwing codes, the battery issue here sounds like the most likely part.

 

Thanks all for the replies. I took a look at the heated seats install and they tapped into a 12v ignition power wire so I un-wired that today and then drove around town for about 40 miles with no issues. I also realized that the issue only happened when both seat heaters were on, so I think that was messing with the smart entry system. Will know for sure over the next few days, and if that turns out to be it, I will rewire the heaters direct wire instead.

 

I have a ton of gizmos added to my truck and so far have avoided all factory wiring with the exception of a single fuse tap for relays. I put a Blue-Sea marine fuse block under my hood and have about 6 circuits (lights, usb, etc) running off it. Some are full time live (USB) and everything else uses relays to provide power from the switch. That way if something goes poof it is completely separate from my trucks electrical system. I have some heated seat pads I need to get to soon as it is getting damn cold this weekend

 

I'd start with a new battery. SDHQ makes some high quality battery terminal connectors. Are you sure your fuel pump isn't causing some of these problems? There's a recall on fuel pumps on some of the newer Tacoma's.

 

Was the blue-Sea easy to install? It looks complicated

I hate doing electrical work

 

Thanks @mhornco makes a ton of sense. How do you wire in the relays to come on with the switch? Are you tapping into some existing wiring there?

 

Thanks, pretty sure the seat heaters were the issue. I checked my VIN previously and there were no open recalls.

 

Pretty simple. I have it over on the drivers side just behind the battery. It is mounted using an old piece of sheet metal I found, though you can actually buy a mount for it, but like most aftermarket stuff it is ridiculously expensive. The relays are in a row across the back ( although now you can buy a fused box with relays built in which cleans things up). I also bought a 100amp breaker to protect the whole thing. Just ran a positive off the battery through breaker and to the positive side of the box, then a negative off to the negative side. I have two of my relays getting their trigger power from a fuse tap in the cab as I did not want to be able to switch them on when the vehicle was off (the trigger draws very little power on the order of milliamps). Those were for my light bar on the winch mount and for a USB and 12v outlet i put on the back of the center console for back seat drivers to use. I put 12v in the bed, and for wiring the shell which are live all the time, as well as a couple more in dash USB outlets which are live all the time. Those circuits are each fused through the Blue Sea box but of course no relay for them. I have other lights and a compressor which are run through relays as it is never a good idea to have heavy amp loads going through the dash. All I have coming into the truck then is a series of very light wires (14-16 g) that simply do the switching, heavy stuff is in the engine compartment or along the chassis to the back of the truck.

 

If you don't plan to use an aftermarket brake controller you can use that circuit to power the heated seats.

 

Here’s a schematic of a typical relay connection. Rewire the seat heaters with a relay and tap your 12 volts off a non critical circuit.

 

Sounds like potential fuel pump issue

 

My money is on the aftermarket seat warmer. Remove that and see for a couple of days.

On a side note, no need for a seat warmer. It’s a luxury item. Beside, you can easily warm the seat naturally (fart around for a few minutes). It will be warm and toasty in no time. Caution- Heads up- it may smell a bit pungent after operating the natural seat warmer. Problem Solved!!

 

Haha, thanks for a good chuckle! That turned out to be the issue... we disconnected last week and I have driven many hours since with no issues so I will be rewiring them direct.

 

thanks. helpful.

 

Appreciate the suggestion. However I am about to put a lift on the truck with air bags and a brake controller because I tow quite a bit so I won't be able to use that circuit.