I bought a 12 4Runner limited last September from a local dealer and it’s been a bunch of problems so far.

It started with hard starts so I had replaced the battery before the weather got cold and would have an issue with a dead battery one cold day. Turns out that the battery really wasn’t the problem. Any time the weather is below 30° that battery won’t last more than three days, if it’s really cold one day tops.
Obviously a parasitic drain. I tested it at least three times and couldn’t find anything besides a huge draw of amperage on shutdown. Somewhere I have three pages of diagnostics that I did. Took it to the dealer they found nothing.

A few weeks later all the traction control lights are coming on at startup or while driving with the 4lo light flashing. It does this sporadically. I bought a new neutral safety switch or what ever they call them for the Toyota’s. I never replaced it because the problem went away.

Everything was fine all through the summer, last week we had our first cold snap low and behold dead battery again after sitting three days, and then on my way to work tonight I hit a bump in the road the same one I hit every day because it spans the whole highway and all the traction lights come on and start flashing and this time the tach stops working and the speedometer starts going haywire. A couple hundred yards down the road the speedo and tach come back to life and only two of the traction lights are left glistening away. Here is a video of the cluster going haywire. YouTube

I know the first question will be aftermarket parts.

Yes it does have an aftermarket radio but the parasitic drain was happening before the radio had to be changed out because it stopped functioning properly.

Another is remote start yes it has one but I have no idea if it’s factory installed or aftermarket.

One of the other problems I had was with both of the rear calipers freezing on me.

Another issue I noticed is large drops in the voltage when I apply the brakes. Sometimes it will drop almost down to the first hash mark

So what I’m hunting for is if anyone else has had any of these problems with a 5th gen?

Everytime I do a search for my issues it’s always the 4th and 3rd gen trucks.

I'm sorry but it sounds like you bought a rental/poorly modified vehicle.

My suggestion is confirm if that remote start is aftermarket or not. If it is you need to remove it. It could/may be tied into the harness in many places so don't start hacking without tracing everything first.

Do everything you can to return the wiring harness to stock. Remove the outside variables.


I'm going to guess somewhere in that remote starter there is a connection (or many) that's shite. So in contracts in the cold (loosening the contact) and gives you weird issues but, in the summer it's a non issue (contact expand with the heat). Not a betting man but I would put a little down on that.

I agree, start with removing that remote starter and fixing the harness properly. If you can't do it get it done professionally and make sure the shop knows what they're doing. I worked in the service dept of a dealer and that was the most common electrical issue, a poorly installed remote start system.

This may sound stupid, but are the battery terminal connectors properly tightened?

Flood damaged maybe? That's a lot of issues.

Sounds like you worked at a dealership that likes to point fingers and do part swaps. Actual troubleshooting is a lost art.

I posted this in a different thread recently if you need something to compare results on a Limited with prox key. If I leave my truck sitting for 3 days, it will be a little sluggish to start. If i leave it outside for that amount of time in the cold I would not be surprised if it didn't start. I've also killed the battery several times on mine which diminishes the longevity each time its gone dead. It's also a cheapo walmart battery.

First thing that came to my mind too. Back in the day I worked on some flood damaged cars. The problems from water getting into electrical connectors and then corroding them, always cropped up some time after the flooding occurred. Often years later.

I'd start looking for signs of flood damage: Rusted interior fasteners, corroded electrical connectors, etc.

Everyone’s a mechanic nowadays = Parts Cannon

Add the alternator to that list of checks.

Of all the modded cars I dealt with, electrical troubleshooting was my least favorite topic. I say trade it in if you still can, at least 4Runners hold their value at resale.

I would eviscerate the dealer on social media unless they are helping you with at least some of this. Very slim chance they knew nothing about all these problems before they sold the vehicle to you.

Sorry to hear about your troubles. Was this at a Toyota dealership or used car lot? Did you have a pre-purchase inspection done? I'm not mechanically or electrically inclined enough to deal with all those issues. I'd recommend having an independent Toyota mechanic inspect it. Maybe get in contact with Mainline Overland and see if they can either do that or know someone who can. They do a lot of builds but also do maintenance and service as well. If it ends up being too costly or too much of a headache then it sounds like you may have to dump it and take a loss on it. Although hopefully that is a last resort.

Contact Us - Main Line Overland

Dealers get a lot of cars at the auction, so they may not know the history.

It's also possible the owner was having the same problems (probably because of his own effed up mods) so he traded it in just to get rid of it.

It's a 2012 so might have been bought in 2011. Hurricane Sandy hit in 2012.

One of my automotive professors way back when had a saying, "The weirder the problem, the more likely it is a bad ground". A few years as a technician proved that statement more than once.

Based on what you described, I would be very suspicious of a bad ground, whether that's a corroded cable or loose connection, or corroded connection.

The voltage drop on brake lights, the control units going crazy hitting bumps, the voltage draw (which sounds like a controller struggling with shutdown messages) would all be enabled by a poor ground.

Disconnect your battery cable cables and test the negative cable to the engine bock with an ohm meter. It should be zero. Check the negative cable to a bare body bolt. It should be zero, or very very close. Do the same to the frame. Anything above 1 ohm, and it needs further inspection.

You have ground bolts to the engine block accessible through the fender wells on both right and left. Back the bolt out, scrub the cables and mounting location with some scotch brite or sand paper and then retorque the cable and bolt.

Check your fender and frame grounds. If you have a trailer plug, make sure you don't have a green fuzzy petri dish experiment growing under the cap.

Check the wiring under the dash board on the left side kick panel to make sure someone's left foot didn't previously rub or stretch the wires.

Only after I had checked all this and did volts drops across the ground cables while the vehicle was running, would I move on to trying to diagnose the actual controllers or instrument panel.

did you test your alternator?

also what method did you use to check for a parasitic drain?

@Narat_524 it sounds like your a SME in the matter. COULD you make a "secondary" ground to run between various points (Alternator, etc) to troubleshoot?

I bought a brand new 2018 ORP. I can’t leave it set for more than 48 hours else the battery is 100% dead. I had to replace my Stock Panasonic battery inside of two years. Usually people get 4-6 years out of them.

I have no electrical mods, never been in an accident, don’t abuse it, etc.

I haven’t tested for parasitic drain yet... recovering from surgery. I plan to this weekend. If I find anything I’ll post in this thread. Sounds like others have issues letting them sit for more than a few days too though.

I know this doesn’t answer any of your questions, but at least know you’re not alone