Not your usual bad starter problem on a 4.7. My 2000 Tundra simply won't shut off. Any time the battery is connected, the truck just cranks and cranks until the battery dies.

The problem seems to be in the wiring. The starter relay always has 12v and ground, so it's always energized. This is not right. It's not in the ignition switch as unplugging that makes no difference.

Putting the truck into gear does cut the starter. So when you're driving, everything's normal until you hit N or P, then the starter kicks in again.

I don't have a wiring diagram for the truck, so I don't know where else the starter relay might be getting this phantom power. It just developed the problem on its own, I didn't make any changes to it at all.

Any ideas?

 

In case anyone comes across this in a search...

while my voltmeter did report power at the relay, a check with a test light showed it to be quite low power. It appears the 140,000 mile relay was tripping over easily with just a little bit of phantom power. Changing that out ($28 for the part at NAPA) seems to have solved the problem.

 

I have a similar problem and was thinking it was the relay. Thanks for the info

 

04, 4.7 tundra running fine then parked for half an hour came back and when ignition key turned, starter comes on and engages with engine but engine doesn't start. Then when key is released or turned off starter continues to run for about 10 sec. I found a relay in the engine compartment fuse box. I removed the relay and starter wont run so assume this is the relay being referred to. After putting it back the starter would go off when key is turned off but still ran when key relaxed to on position and engine still turns but wont start. I order a new starter relay from dealer ($80) hoping I would plug in and go. No such luck (non refundable part) and starter is back to running even when key is off, still turns engine. I took the relay out and connected a switch between the two copper terminals. With the key off and using the switch the starter motor turns on and off normally. With the key turned on and using the switch the starter seems to on and off normally but engine will not start. With relay back in and using key the starter is back to turning off when key is turned off. So taking the relay out and putting it back seems to temporarily stop the run on in the key off position but not in the relaxed on position. I also noticed when the relay is removed and key turned to on there is whirring sound like a small fan coming from area of the starter. Could the starter run on be associated with a bad ignition switch? Also in all these scenarios why wont the engine at least try to start?
I invested in an $85 code reader that is throwing codes P0335, P0340 and P0300. Across these codes the common cause is the Crank Shaft Sensor (CKP) and or the (CMP) Cam Shaft Position Sensor. All the other potential problems could be caused by either so that’s where I’m going now. Since my situation seems to be other than my starter I have started a new thread about the sensors

 

I was just wondering if either of those sensor you change fix the problem? Having the same issue and I have changed out the relay,starter,ignition switch.

 

I had change relay out for same problem also and it came back with same issue later, was just wondering if your ever came back and what you end up doing?