P0974 plus knock sensor code

Here is a little background. 2009 tundra with AB60F throwing P0974 code. CEL is on, 4 lo flashing, VCS flashing, Traction control on. I changed the S1 solenoid and it is all still on. Truck seems to not go into 1st gear when in "D" but if put in manual it will work fine with no slipping or anything through gears. Any other ideas as to what could be causing the code? All internal wiring inside the trans pan looked good, only thing was on the connection where the solenoid harness hooks up on the outside of the trans a couple of the holes on the female connector looked to have some debris in them. Cleaned them out and still doing the same thing. It did also throw a code for a knock sensor before this all started but it went away so I assumed bad gas. And it did throw the knock sensor code again the first time it started the P0974 but after i cleared them it hasn't came back on. Also there is a hole in one of the exhaust pipes before the cat, don't think that could have anything to do with it but I really am clueless on this type of thing

 

My only experience with knock sensors is in a Lexus RX300. But when the knock code threw on that vehicle it precluded the tranny from shifting into the final gear at top speed.

Doesn’t match your situation but it does provide a link b/t knock sensors and shifting issues.

Replacing the knock sensors was doable on that car. You had to take everything on top of the engine off including both upper and lower intake air assemblies, then remove the knock sensors from the top of the engine block. Dealer quote $1,500. DIY about $250 for the part and replacement air manifold gaskets. But that was a Lexus.

 

I’ll add this as well - the issue was with the sensor, not behicle performance.

My understanding is that at least part of the purpose of knock sensors is to prevent damage to the tranny from shocks in force from the drive train from mis-timed ignition. So the KO sensor is tasked with locking out certain shift features, so if it goes bad it can manifest in certain ways / stuck shift positions depending on how the sensor malfunctions - eg circuit open, hogh voltage, low voltage, etc.

I could absolutely be wrong, but my extensive reading about the issues I was having at the time convinced me that I was not having a performance issue but a sensor issue.

 

Thanks for the info. I was kind of leaning towards the knock sensor or wiring for it after I did some reading as well even though it's not throwing a code for it at the present time

 

I can dig for them on the Lexus forum I used and/or try to find them for Tundra (Sequoia is basically the same) but there were some short-circuit options for testing whether it was the knock sensor. You can insert an unwound paper clip between two ECU ports to signal all-clear. It should correct the shifting issue.

Have you cleared all engine codes? You’d have to in order to try a short-circuit troubleshoot.

 

I can clear the code but it comes back on almost immediately. If there is a short circuit option it would be very helpful. I can't find much info at all on the P0974 code, and I wish I could remember the knock sensor code

 

I would start looking for rodent damage. I was a Toyota mechanic for a while and the majority of the time when there was a knock sensor code it was due to rodent damage.
The intake and the foam around make a nice bed for rodents.

 

I have read that on several places. I'm going to try and check on it all this weekend, just trying to narrow it down and see all options in case it's not the problem. The only thing that makes me wonder about the knock sensor is that it's not throwing a code for it still.

 

Does code P0330 ring a bell? That’s the code when it happend on my Lexus.

Here is the Lexus forum thread on the wiring hack. Not sure if the same option exists for a Tundra.

https://www.clublexus.com/forums/rx...p0330-knock-sensor-15-min-hack-repair-16.html

 

Ya my knock sensor just went out in my 2002 Lexus RX300 a month ago I almost smoked my tranny. $1447 to fix it.

 

Got it fixed today. Ended up being the solenoid wiring harness. The pin on the connector for the S1 solenoid was broke. But now I have another problem, when I was taking the old harness off, the bolt that holds the connector on the top of the transmission snapped off and I can't get it out and there is no room to work with in there