2007 Tunda v8 5.7 4x4 P0717

So I had my first MIL on my Tundra for the 5 years I've had it. It threw a p0717 "Input/Turbine Speed Sensor A Circuit No Signal". It's not a permanent code. And it had to happen a day before I was going to tow the boat to the lake.... fun times. I'm going to drive it around to see if it was a fluke code, the performance has been fine up to this point. Googling the code leads me to think it's a bad sensor or an internal transmission problem. Any guys here familiar with Toyotas that have seen that code? Am I most likely looking at a transmission rebuild? I'm an Acura tech so I'd be thrilled if someone here knew of a pattern of those sensors going out and I'll put one in. If it's internal, I'm not touching that trans...

To give some more info, I cleared the code and road tested my truck again. It took a few miles, but it eventually coded up. Not a fluke. But no slippage or other symptoms.

Odds are if the is no signal is from a buildup of metalic/(magnetic) metal. But i would check the wiring for circuit integrity. Ohm wires from trans conector to pcm for i.s.s. circuit. If they test ok then your going to have to open tranny up and check for metal flake stuck to sensor also the vehicle speed sensor can suffer the same way pull it as well and clean them off. The i.s.s. and the v.s.s. may not be bad just have a buildup of the metal on it. Depending on how much is in the trans pan it might need a rebuild.

I hope I don't since 111k seems a bit early for that. I did find that the VSS and the Turbine speed sensor actually have the same part number according to Toyota's parts website. If I swap them and the problem moves, I have my answer.

So I swapped the sensors, VSS output unchanged and now the light won't come back on. I found a PDF of the Toyota service manual and both sensors measure in the right resistance range. Gotta love those intermittent problems. Can internal transmission wear cause this code?

When you swapped them did they have any sludge on them? Also did you look into the iss hole for anything sitting in the opening? Most of the time when an iss does not read a signal it can be from one of a few things...
Sensor bad (deformed waveform shorted sensor)

Pinched wire or almost broken/heavily corroded wire (look for (dark brown to black or green crusty) wires at terminals

Sensor ground (either pcm grounded or case grounded)

Bad connection (pin fitment)

Bad internal harness (if applicable)

Debris stuck on iss (internal wear and tear of components) common for high mileage vehicles

Sensor ring out of position(very rare)

That's what I figured too. Oddly enough, the VSS had more stuff on the plastic shaft of the sensor than the ISS. Both magnetic tips of the sensor looked similar. I know on the Acura transmissions of old, the shaft bearings would blow out and the gears would eat into the mainshaft and countershaft sensors(and sometimes short the 5v ref) that's what I feared with my truck. I looked in the bore of the ISS hole with a mirror and saw what I expected to, transmission guts, nothing looked out of the ordinary.

The connector looked clean, pin fit was good. No corrosion. We don't see much of that in my part of California. Maybe heat related? The cat is right next to it. I went and drove 6 miles in the manner listed of the code enable criteria. My OBD phone app says 6 miles since DTC clear. I'm really hoping it's an intermittent bad sensor and it throws a VSS code next...

I hear ya... the iss gets more filtered fluid than the vss so if you have it on one theres a chance for the other. Just means the part wearing out is closer to the vss with the fluid flow 1st-4th clutch or a needle bearing washer eating itself just depends on driving habits and fluid changes.

Could be the ISS had got "weak" to the point it wouldn't work reliably in the ISS position. VSS position might have less air gap, or some other difference, which allows it to work there. Just another possibility on top of the wiring problems Hardtop mentioned which could've been "fixed" by moving the sensors.

That said I'd still drop the pan to look for signs of impending mechanical failure. Better to find out on the rack than on the boat ramp...

I think I'm going to drop the pan, R&R the filter and service the transmission oil if the light doesn't come back. Yay WS fluid prices! Thanks for your thoughts guys. I thought about doing the reman myself if it's needed but the Toyota special tool kit for the trans is $900 and I haven't had my hands on planetary gears since tech school, we just replace with reman units at my dealer. I'll either buy a Toyota reman or have a reputable tranny shop do it...

I would just change fluid out with a filter. See how it does then 3 months or so drain fluid and check for flake in fluid. Though it depends on what ya find. Best of luck

While a service can never hurt, I'm thrilled to report that I have a pending code for p0722, the VSS circuit now has the trouble. Intermittent sensor failure confirmed. The suspect sensor coded right up in the ISS hole. It must have been happier in the VSS hole. I guess I need to really consider buying a scope so I can see the waveform. The repair manual had a known good one to compare to, but I just didn't have the equipment diagnose the circuit. At least swapping with known good saved me here.