2006 Tundra - Electronics Saga - pls help!

Hey all -

First, I just love my 2006 Tundra. It's the "crew" cab - plenty of space for the kids.. it has a bit of body damage and such, but I just love the thing and want to drive it forever! Unfortunately, I've had about a year long saga with something I think is in the electrical system.

As of -this minute-, the truck will start, then immediately die. However, there is a long and lengthy story leading up to this point.. and ultimately, whatever is wrong with the truck hasn't been found yet. I -think- it's a corroded wire somewhere, but I am not sure.. and am only a rudimentary parts mechanic, and have never done anything with automotive electrical.

It started back.. maybe a year ago, when I'd turn the key, and there'd be nothing. No "click click click" - rapid or otherwise, nothing. Only one "click" - but that same "click" happens even when I just turned the key to the accessory position. Another turn of the key, and it'd magically start. Then, as time went on, I'd turn the key, and I'd get nothing (by nothing I mean, just that one click)... a couple times, then eventually, I'd turn the key and it'd start.

Other days, I'd turn the key and it wouldn't start no matter how many times I tried it, UNTIL I would simultaneously use the window button to roll down the driver side window as I was turning the key.. THEN it'd start. Making me think... hmm when I put more electrical draw on the system, the car starts.

ALSO, sometimes when I WOULD get it started, the truck would run for a minute, or maybe a few, then just die.

Stepping back, I'd had the alternator replaced on the truck maybe 2-3 years ago by a non-dealer mechanic. Not much longer after, I had almost the entire A/C system replaced because that went out, also a non-dealer mechanic.

On this particular "not starting" issue, I've been working with the Toyota dealer only. First, they replaced the starter. Started a few times like that, but then in a day or so, went back to not starting reliably. Probably just got lucky those few times it started. To rule it out completely, I replaced the battery. Even with a new battery, very quickly the truck it wouldn't start at all, so I took it back. They then claimed it was the ECM, that when I turned the key, power was going into the ECM but not coming out... so they recommended a new ECM, of which I was skeptical, because I was told that if the ECM was bad, all kinds of other issues would be happening too.. but, I had them do it anyway. So they replaced the ECM (brand new OEM, reprogrammed it, etc).. and it started enough to leave the dealer.

Next morning, it didn't start again. So the dealer towed the truck back to their service center, paid for a rental for me for two weeks, etc. Very good of them and I like the service person I'm dealing with. Ultimately, they couldn't find the actual issue, so they ended up bypassing the ECM's starting circuit (?) - they just wired the ECM starting "in" wire directly to the ECM starting "out" wire, and again, it started a few times. I really thought we had it fixed then, even though it wasn't really the "fix" - just a workaround. It was fine with me, I was happy to be driving it again.

Now... I just drove my kids to school, and driving on the way back, the truck just died. Luckily, I was on a 25mph road, just prior to a stop sign. I rolled it to the stop sign and hit the brake and put in in park. I tried starting it and starting it, it just kept starting and immediately dying. Then I unplugged my DC charger from the 12v to my phone, and luckily it started and kept running. I was able to make it home.

Now that the truck is home, it just starts and dies. Not sure it even really "runs" at all before dying now. I tried it maybe 15 times, nothing in the DC ports, I even disconnected my stereo. I turn the key, I hear the starter, things move for a second (or less)... then it dies.

OH and here's another weird thing... on this drive back from school (where it died) - after I got it back running, my stereo would just start shutting itself off. I turned it back on, played tunes for another ~5 min, then it shut off again. Like, completely off, resetting all its settings - as in, it got zero power. The stereo is aftermarket and has been getting kinda flaky lately anyway, so maybe not related.. but maybe is?

I'm out of ideas. I think with some guidance I could troubleshoot it myself, I have a garage full of tools, and I work on small engines and outboards in my free time. I have a multimeter.. etc. - could the "new" alternator be bad?

If you've read this far, thank you in advance! I really do just love the truck and ultimately would love to just keep it running, and then some day have the body work done and have it painted!!

Thank you!!

 

All your symptoms sound like they could be either a bad battery or ground/cable connection, but I would assume the dealer has ruled all those out?

I have seen batteries that tested good on a basic battery tester (i.e not load tested) cause all sorts of weird issues that turned it to be a bad battery when load tested. The first thing I would do is have the battery load tested (even if you replaced it after all this..just to completely eliminate it) and then I would check all you cables too from the battery and all your main grounds.

 

The dealer claims they have ruled all that out, but I am skeptical. Yes, I did forget to mention I replaced the battery too, it's just a few weeks old (from the store, that is) - and the old battery they claimed was fine and "just needed a charge." So I have all kinds of expensive new parts I didn't need...

... I have the Haynes manual... is that the best place I should look to start tracing the grounds?

OH and here's another weird thing... on this drive back from school (where it died) - after I got it back running, my stereo would just start shutting itself off. I turned it back on, played tunes for another ~5 min, then it shut off again. Like, completely off, resetting all its settings - as in, it got zero power. The stereo is aftermarket and has been getting kinda flaky lately anyway, so maybe not related.. but maybe is?

 

Well, it's not alot if work to check all the cables and grounds, so I'd still do that first...

 

Ok, will do. Should I use the Haynes manual for guidance or are there better wiring diagrams I should consult? And in general, do you just mean unplugging every harness I see, checking for corrosion in the contacts, etc? I can search YouTube in the meantime in terms of troubleshooting auto electrical ground..

 

Here is a link to the 05-06 FSM

https://drive.google.com/file/d/0B-5MhfqaHsHObmt6RDVhOGtKWjA/view

Check all the under hood grounds and any connections to from battery.

 

I'd add a new ignition switch to the list. Wouldn't be the first time we've seen one bad.

 

No kidding... yea I guess that'd make sense, it could definitely be dying due to a bad ignition switch, right? Dealer claimed they checked the switch but again, I'm skeptical..

 

Thank you for the manual!!

 

It's behaving like low voltage...check the alternator output/voltage regulator. Charge the battery overnight to full capacity (~14 volts). Drive it around again until it dies, then check the battery voltage...I bet it's less than twelve volts. Just a hunch...

 

Ok, and if this happens, it's either the alternator, or the voltage regulator? Is the voltage regulator -on- the alternator? Thanks for the response!

 

Update - tested the alternator - when the truck is running I’m getting 14.14 volts at the battery. I then turned my lights on, my radio on, plugged in my phone to the DC to charge, put the truck in reverse to turn on the aftermarket dash cam... and the voltage dropped to about 14.04. Then when I turned everything off (lights, unplugged charger and radio, etc) the voltage only got back up to 14.07. Is that normal?

 

Normal, anything over 13.5 while running is good.

 

I have an ultra gauge in my 06 Tundra and my voltage stays around 13.6 - 13.8 volts most of the time when the engine is running. 14.04 - 14.14 sound like it's working as it should

 

FSM iirc states proper spec for 2002 (100 amp alt) at between 13.3-13.6 volts at battery reading.

 

+1 for ground and ignition switch re-tests.

 

All the ground points I could find tested 12.8v - same as battery, but I’m certain I didn’t find all of them... was kind of hard to tell from the service manual diagrams what points were the actual grounds. I found the obvious ones going to the chassis, but didn’t find the ones that are actually on the engine..

 

And I’ll need to see how to test the ignition switch.. will YouTube that one.

So grateful for all of your responses! I managed to start it again tonight over and over after fiddling with some of the harnesses.. might not be related, might be just because it was sitting and hadn’t been running.. but the thought of getting rid of it was really saddening! Def would like to try to truly identify the problem and fix it, otherwise I’ll never be able to confidently travel in it with my kids or tow our boat with it, etc..

Still also don’t know why the radio randomly was shutting off on the way home, and nothing else..

 

Probably need to test resistance of each major ground wire. I have seen them corroded inside of a perfectly good looking cable.... volts are good, but may not be able to carry amps if it’s corroded.

 

The radio thing is what makes me think ignition switch. They're cheap enough to grab a new one to try out, about $30 from Rock Auto or Amazon for a Dorman one.

 

Hmm ok, I'll get under there and check the connections with a multimeter I guess (saw that on a YouTube video). My wife is very much urging me to get a newer one so time is of the essence!

Side note, is there a _certain_ ground point that I should check that would cause the engine to die while running? Or could _any_ engine ground point being faulty/loose cause the engine to die?

 

This sounds like a ground issue to me. I had a truck years ago I had similar problems with. Would shut off and simulate a dead battery I replaced the battery and battery terminals in a Walmart parking lot. Not long after that, maybe a week I continued to have the same problems and replaced the alternator. I found it was ultimately a loose ground under the hood.

 

Thank you! I am having trouble locating all of the grounds. The ones on the "outer rim" of the engine compartment are obvious, but the service manual notes others that I am having trouble pinpointing. Would someone be able to offer some additional guidance / photos as to where all the ground points are?

Also, measuring ground wire resistance was mentioned - is there an acceptable resistance range for the ground wires?

Thank you!

 

I removed each of these 3 ground points individually and tried to start the truck in between; each time it started and kept running fine. In fact, ever since I fiddled with the wire harnesses last night, the thing won’t start and die any more..

Really would like to find the failure point so I can reproduce the start-and-immediately-die, and “know” this issue is fixed. Otherwise it doesn’t sound like my wife would ever feel safe driving it let alone towing a boat with it, and I don’t blame her..

 

More pics of the engine in case anyone wants to point to other ground locations to check. Having trouble locating the non-body ones using the service manual..

 

Also... just was able to reproduce the start and immediately dying... once. I started the truck, plugged two things into my DC slots (phone charger port+backup cam in one, dash cam in the other) - turned on the stereo and cranked it loud, turned on the headlights, put the blowers on full (medium temp, A/C button on) - ran it like that for about 10 minutes just sitting idle.

Then I shut it off, left the DC stuff plugged in, cranked it.. it started and immediately died. Then I tried again, and it started (still with the DC stuff plugged in).

Definitely feels exacerbated and more prevalent any time I use the DC stuff... and I never use it unless the engine is running, like even after I'd drive the kids home from school (20 min), using the radio and phone charger/etc.. the next time I tried to start it, it wouldn't start. Unfortunately, even when I don't use the DC stuff, the no-start (now the start-and-dying) will sometimes still happen. Otherwise I'd just never plug anything into the DC ports... Overall, does this point to any other/different issue?

 

I think @Festerw may be on to something with the ignition switch...they are cheap, especially if you go non-oem.


Despite your dealer saying you checked it, I would replace it. It's not that expensive (especially if you go aftermarket) and the first two symptoms here point to it...

https://www.700r4transmissionhq.com/toyota-tundra-bad-ignition-switch-symptoms/


https://www.rockauto.com/en/catalog...l-switch+&+relay,ignition+starter+switch,4700

https://parts.mcgeorgetoyota.com/oe...1bmRyYSZ5PTIwMDYmdD1zcjUmZT00LTdsLXY4LWdhcw==

 

Ok, will do. I guess me jiggling the key while it's running having no effect on making it stall isn't really a good diagnosis, right? I tried that, tried to pull the key out while it was running, it won't pull out, jiggled it a little and nothing, kept running. I'll get a new one and give it a go.

If someone would want to let me know the other ground points to check on the photo above in the meantime though I'd be grateful..

 

So on your photo from above, there is another ground on the driver front cam area, 2-3 brown wires going to it, and then same side, on the back of the engine right below the air injection tube.
Also check the ground on the back firewall to the engine block.

 

Okay, will do. But if it were one of the grounds, would the truck not start if I disconnected one of them? Just trying to understand the expected behavior. (I was hoping I could reproduce the no-start or start-and-die issue by disconnecting one of the grounds) - but so far this hasn't been the case with the grounds I have disconnected thus far.