Tundra Dies after start, in Reverse + Parasitic Draw (With Potential Solution)

I've had this problem developing for quite some time and it's finally come to the point where the truck was no longer drivable and had to be towed to the dealership. I wanted to make this thread in hopes it helps someone else with a similar issue, at least some guidance or direction.

The stats:
2016 Tundra SR5 CREWMAX: 193xxx miles
Aftermarket Radio, Viper Remote Start Alarm, Warn Winch, LED Lights (this is relevant).
New Optima Yellow Top Battery installed a couple weeks ago



The truck has progressively gotten worse to drive. From shuttering (quickly stalling) when hitting bumps, to outright stalling and needing to be restarted while in drive. For some reason it seemed to help once the truck was warmed up but lately not really. As of a couple days ago you could start it, put it into Drive or Neutral, but in Reverse it would immediately die. OR...sometimes you could put it into reverse and it would idle with park brake on but as soon as you touched the gas: dead.

Add to all this: a parasitic draw smoking my batteries over time.

Had a buddy come over who wrenched for a long time, brought his meters and we went through all of it. Pulled every fuse, systematically worked through all the aftermarket stuff listed above and nothing appeared to be the source of the draw. We pulled the dash apart, crawled all through the engine bay and under the truck inspecting for loose wires and grounds, nada.

Put the truck back together and no improvement, so I had it towed to the dealer.

Dealer Diagnosis:

A/T - Shift Solenoid Position Sensor/Switch: CONFIRMED VEHICLE WILL GO INTO DRIVE AND THEN DIED WHEN ATTEMPTING REVERSE. PUT VEHICLE ON LIFT AND RAN HEALTH CHECK, FOUND NO CODES STORED. EVENTUALLY IN AIR VEHICLE DID NOT DIE IN REVERSE, SUSPECT INTERMITTENT ISSUE. FOUND IN VEHICLE ENGINE ECU DATA LIST, VEHICLE CAN SEE WHEN SHIFT LEVER IS MOVED FROM PARK THROUGH DRIVE. INSPECTED OVER PARK NEUTRAL SWITCH AND FOUND NO OBVIOUS SIGNS OF DAMAGE , REMOVED CONNECTOR FOUND CONNECTOR OK. TESTED CIRCUIT, FOUND CIRCUIT OK. RE INSTALLED CONNECTOR TO PN SWITCH , NOW VEHICLE WILL NO LONGER START. FOUND ON DATA LIST, NEUTRAL POSITION SIGNAL ALWAYS REMAINS OFF INDICATING VEHICLE IS NOT IN PARK OR NEUTRAL. CONFIRMED VEHICLE HAS PARASITIC DRAW AT 0.100 mA WITH ALL DOORS CLOSED, LOCKED, HOOD LATCH SHUT , WINCH , AND LIGHT BARS DISCONNECTED. SUSPECT DRAW AND PARK NEUTRAL SWITCH ARE RELATED SINCE VEHICLE DOES NOT KNOW IT IS IN PARK OR NEUTRAL. RECOMMEND STARTING WITH REPLACING PARK NEUTRAL SWITCH AND THEN PERFORM PARASITIC DRAW TEST AGAIN

Final Thoughts:

It would seem everything is related, the service advisor called me and said the part would be here tomorrow and installed, roughly around $900 OTD fixed. Googling things had me all over the place, transmission problems to everything else under the sun. Pretty sure this will handle it, will update if that changes.

 

Please do share when it gets handled.

How much did the diagnosing cost you so far?

 

Ooooof; $900 for a possible fix is a tough pill to swallow. Hopefully that is all it is and you’re back in the road soon! Sounds like the dealership actually performed a robust diagnostic and took your issue seriously!!

 

So I wanted to make an update. I picked up the truck yesterday, and so far so good. It starts and runs great, it performs as it should and I realize now that this has been an issue for quite some time.

I will say, before when I would disconnect and reconnect the battery the truck would try to start on it's own. Now that the switch on the side of the transmission has been replaced, it does not do that. It's so very strange. It fires right up, shifts into gear, does not shudder or want to stall at any point when driving or put into gear. It does seem that the draw was related to that faulty switch.

These trucks are great but if a small component fails, there can be issues. It works normally now so who knows...

 

Great to hear that they found the problem. Seems like they did a thorough job. I wish the dealers here were as good.

 

I will say there was one issue that I felt wasn't handled correctly, I reached out and expressed this before leaving a review (they sent an email asking for one). The Service Manager called me, we spoke for about 15 minutes and he has offered to make it right. So far, seems legit.

 

In your OP, you mentioned the LED's being relevant. Did I miss this point?

 

They wanted to check every aftermarket part to see if it was contributing to the draw, and since the LED Light bars were hooked to the battery they were a consideration as well.