Urgent - 3.5L/Auto 'D' not indicated - SR5 moved then lost forward gear

I purchased the SR5 DCLB 2 years ago from a dealer. We have experienced this lack of drive gear indication previously but it went away on its own. Our son was just about to leave to go back to college (2.5 h drive) and this issue has returned. What is the significance of this?

In view of my history with this issue I decided to try a brief test drive to the end of our road (3 mi) and back. I was able to navigate out of our drive and get onto the road then lost drive gear. So, in addition to no console or dash indication of 'D' being engaged I also had no drive gear.

I will try another test drive but unless someone can give me definitive information regarding what this problem is as well as how I can sole it and no it will not return it appears we are driving our son back to college this evening.

Thank you.

 

Drive your son to college first ... education more important than the transmission ... my opinion.

Let negative battery cable be off for at least 30 minutes. Could be a dying battery causing ECU to lose power (that is a wild-assed guess) and ECU loses its mind. If you have not put a new battery in then maybe a trip to Walmart (many say those batteries work and there are Walmarts everywhere for warranty). If so, get a

$100 NOCO GB40 1000A UltraSafe Car Battery Jump Starter, 12V Jump Starter Battery Pack, Battery Booster, Jump Box, Portable Charger and Jumper Cables for 6.0L Gasoline and 3.0L Diesel Engines

NOCO GB40 to allow boost battery if needed ... I have one and no apparent battery problems yet.

Could linkages or other physical/mechanical connections.

 

Test Drive #2 - No indication of 'D" being engaged on the console or the instrument cluster but I was able to complete the round trip to the end of our road and return home.

 

New AGM battery that I just took off the maintainer before backing the SR5 out of the out building. I'm suspecting auto instrumentation improperly detecting and communicating 'D' to the remainder of the control units.

 

Try the 30 minute disconnect if you have the time ... things lose their minds for just transient spikes even with good power.

 

Driving our son to school. Battery (-) disconnected. More later. Thank you!

 

The only additional thought I have for today is, 'Does TechStream + VxDiag have anything meaningful to offer me?' I'll resume this search early tomorrow morning.

Edit - It does not appear this diagnostic system is useful or affordable for individuals. Additionally, VxDiag is not recommended for diagnostics according to Toyota.

 

Not sure. I just know these trucks have more onboard computing power than all of the Apollo-mission command capsules combined so they can get cranky if the power spikes (like changing LED interior bulbs without disconnecting negative battery cable).

 

Observations during this second incidence of no indication of the trans being in 'D' on the consoel or the instrument cluster:

1 - I have been 'marshaling' the SR5 from our out building to the drive (for daylight) while doing some rust repair during the last month. This second episode of no indication of 'D' began late during the period where I was moving the SR5 these brief distances. I think the SR5 has been on jack stands the last two weeks of November so no data then.

2- The SR5 successfully moved in drive gear in all of the test drives listed above. It went out of gear almost immediately after pulling onto the road in front of our home only during the initial test drive.

3 - Check engine light illuminates yet not immediately. - Note this also occurred in the initial occurrence of this problem.

4 - Traction Control Off - This indicator also lit just before I put the SR5 away and disconnected the battery yesterday.

Unfortunately, I'll lose all this information as a result of disconnecting the battery. No matter because I do not own a code reader or scan tool anyway. This has to change because I do the majority of service on my vehicles. I wish I knew what to buy...

Is it possible this is an issue covered by a TSB? If yes, I have not located anything. I think there was a TSB for 'gear hunting' that involved the learning process of the auto and some of the vehicles/owners affected by this behavior were know to disconnect the battery for 10-15 minutes. The flashing of the vehicle (maybe just the transmission controller) was also described here in TW to be temporary and last ~ 5k miles. Not so good.

 

You need to pull codes out. Get a cheap phone based app, like Fusion, to read code.
You may have a faulty Position/Neutral switch or some electrical issues.

 

Considering you're doing some rust repair, I'd most definitely start with the park/neutral position switch. Corrosion on these sensors would likely cause exactly what you're describing. While I wouldn't go spending $190 (I think) on a brand new OEM one right away, I'd crawl under there and give it a visual inspection/clean it up and see what happens at the very least.

 

The rust repairs I was performing were localized to the fender flare mounting holes and the set of six bed side support brackets. While some rust is evident on undercarriage brackets and the like I have not looked specifically at the park/neutral switch. I saw some references to this on YT just before we left the house late yesterday afternoon. I have been searching for useful reference information since waking this morning.

I located several useful TW threads/posts in the past hour. I could simply need to lubricate the 'Auto Trans Gear Position Sensor' so that's what I'm going to do and see how much this helps.

https://www.tacomaworld.com/threads...ansmission-range-sensor.836112/#post-29947690

https://www.tacomaworld.com/threads/neutral-safety-switch-replacement.791771/

https://www.tacomaworld.com/threads/automatic-shifter-is-stiff-sticky.759437/#post-27072372

https://www.tacomaworld.com/threads/drive-start-control-malfunction.671942/#post-27028613

I'll post my results after a few test drives.

Edit - After more lubrication w/silicone spray on the shaft where it enters the transmission housing (i.e., the shaft that the shift cable lever connects to) I have had 'D' for three stop/start key cycles on a round trip of ~ 10 miles. So far so good but I'm ordering a new sensor to be safe so that I have it at the house if this persists.

Edit #2 - I found Dom Demeo's YT video on how to replace this sensor. It is a very difficult task in view of the location of the sensor being behind the transmissions cooling lines.