DTC P033D: Knock sensor 4, ie: a mouse ate my wiring. How to fix. (1 Viewer)

[KLF]

Thought I'd do a new thread since it's a specific error that we see occasionally. Just finished repairing mine this evening, so follow along as I show you how to do it, in case it happens to you.

Saturday morning, loaded truck up to go to the dump (it's a New Hampshire thing). Hopped in, fired it up, was presented with a scary scene of the Check engine (MIL) light on, 4LO light flashing, and TRAC DISABLED on the cluster. "Well, this is new". Looked under the hood, nothing was amiss. Engine seemed to run fine, and I really didn't want this bag of stinky trash in my truck any longer than necessary, so off I went, since it's a short trip. I could tell it was not running right, and the trans would not shift higher than 4th gear. Oh boy, this looks bad.

Got it home, popped in my Carista OBD dongle, opened the app, it reported 1 DTC: P033D Knock Sensor 4, Bank 2. Tried a Reset but it came right back. Turns out that particular DTC causes the engine ECU to fully retard the timing to avoid any pinging, and restricts the tranny to 4th gear so you don't drive it too far. Basically a "limp mode to get you home". I've had this happen before with a different car (Highlander) and it was a mouse had chewed the harness on the engine, repair was almost $800 (it was winter, too cold for me to do it). So I popped off the engine cover and pulled off a couple pieces of that foam stuff (what is that foam for, anyway?), and used a really bright flashlight to look where I could, nothing looked chewed or out of order. Resigned that the intake plenum has to come off to access the sensors.

Instructions in the FSM say to drain the coolant. Yup, coolant passes through the throttle body. I'm sure you don't have to drain it all, but I just opened the radiator drain and let it go while I did some other things (drained out about 1.5 gallons). Took about an hour to get the intake off, not that hard, just be careful not to drop anything. You do NOT need to remove the cover on the cowl as the FSM says. As I lifted the intake off, I found this:

"Well there's your problem right dere!" as the saying goes. This was very fresh, some sort of shredded stuffing that I still haven't figured out where it came from. Got it all the stuffing out, yup wires for the connector to that one knock sensor were chewed clean off.

Tips for getting the intake off: I put one of those Werner painting platforms in front of the truck to stand on, then a thick blanket on top of the radiator so I could kneel up there to reach everything. It's not particularly heavy, just be careful. And did I mention don't drop anything? Especially down those intake runners, be sure to put some tape over them as soon as you get the intake out of the way.

Picked up the parts today, had to pay full price from the local dealer as I didn't want the truck down while waiting on shipping. I also replaced the intake gaskets, and a new PCV valve since it had been about 30K miles since I changed it the last time.

82219-60090 Harness for Knock Sensors, $38.24
17171-0S030 Manifold gasket, $17.25 (need 2)
12204-38010 PCV valve, $15.12

So after I got it all cleaned up, I was wondering "why do they always chew that sensor and none of the others?". Turns out it's 2 issues. First, there's a nice valley right there for a cozy nesting spot, none of the others have room like this. And, the 2 wires from the harness to that connector have no protective loom over them, they are exposed for munching (old vs new below).

So I was determined to make it more difficult for them to do this again. I found some scrap angle strut in my pile, cut off a hunk, and put some screws through it to make it impossible to build a nest in that valley. Spray paint to keep it from rusting.

Link to FSM instructions on removing the intake plenum below. You only need to do up through Step 10.

 

[KLF]

(continued)

Then I found a piece of 1/4" split loom in my stash, put it over the wires and wrapped it with tape (I prefer 3M Super 33+ tape for wrapping harnesses).

Put it all together. I was very pleased that the new harness included those mounting clips that are way too hard to remove without breaking them.

Re-installing the manifold is pretty much a reverse of the removal. Torque on the bolts is only 15 ft-lbs.

Best tool for getting the coolant back in is a nifty funnel kit, works great: Amazon product ASIN B00A6AS6LY
Fired the engine back up, no more lights on the dash. Took it for a short drive, shifted fine. Even checked 4LO, CDL, and CRAWL, all work fine now.

Another lesson learned: when you have all those sensors disconnected (MAF, TPS, etc), avoid hooking the battery back up and turning on the ignition. The ECU will flag all those missing sensors and set Permanent DTC codes, even without the engine actually running. I had to test something that was unrelated to the repair, and now I have these codes to deal with when I have Carista scan the OBD port. Permanent DTCs are harder to reset, you have to perform something called a "DTC Drive Cycle", where you drive the car for at least 5 minutes or so above 40 km/h, with a total run time of at least 10 minutes, with no errors detected. This is intended to keep someone from doing a quick reset on an error just before having the car inspected.

This is NOT an $800 repair. I've heard some dealers charging that much (or more), telling stories about "having to lift the engine up". It was that much on the other car for me as they had also chewed up the sensor, so I had to replace that too, and the intake on that car is a PITA to remove.

You can also test each of the 4 sensors while the harness off with a DVM, there should be 180-280 kOhms measured between the pins on the sensors, very easy.

 

[bloc]

Good tech, thanks for posting!

So if I'm looking at this correctly, the harness to all four knock sensors is a separate pigtail that connects to the main harness at the back of the valley via the gray plug between the CAIS valves? If so, that's quite convenient.

 

[TeCKis300]

Nice recovery. Thanks for the documenting this!

 

[KLF]

Good tech, thanks for posting!

So if I'm looking at this correctly, the harness to all four knock sensors is a separate pigtail that connects to the main harness at the back of the valley via the gray plug between the CAIS valves? If so, that's quite convenient.

Yes, exactly. The plug at the rear is... challenging... to deal with. Just be patient, pay attention. Oh yeah, a headlamp is super helpful in this repair! Here's what the full harness looks like (that's the old one):

I'm actually gonna repair that one, as an emergency "just in case" spare.

 

[CharlieS]

So good to see some tech! Nice save, thanks for sharing. I guarantee this will help others of us down the line. Thank you.

You say you prefer the 3M super 33+ tape. Someone pointed me to the cloth tape they use on factory harnesses and it is ok, but doesn't stick like the 3M stuff. What do you like most about the Super 33+? It seems like I've had the adhesive degrade from heat before and cause it to come unstuck, but maybe that was another brand of black electrical tape?

 

[KLF]

So good to see some tech! Nice save, thanks for sharing. I guarantee this will help others of us down the line. Thank you.

You say you prefer the 3M super 33+ tape. Someone pointed me to the cloth tape they use on factory harnesses and it is ok, but doesn't stick like the 3M stuff. What do you like most about the Super 33+? It seems like I've had the adhesive degrade from heat before and cause it to come unstuck, but maybe that was another brand of black electrical tape?

When I had to peel open the trainer harness, I tried a bunch of different brands of tape to re-wrap it, and I found the Super 33+ to be the most flexible and stretchy. It's a little thinner than most, but not quite as thin and stretchy as the OEM tape I pulled off. The Super 33+ also has a higher temp rating, 105dC (221dF) versus 80dC (176dF), which might matter in this situation being down in that V of the engine.

The cloth tape I think you talking about is sometimes called "friction tape". Yeah, not as sticky on things, but it sticks to itself very well for wrapping wires and pipes. It was used heavily in older cars for wrapping harnesses. It has a high abrasion resistance, and some of it is high temp rated.

 

[molanginaeda]

Bravo !!! I actually learn the hardway about this rodent problem on my Sequoia, not LC. Same engine that rodent get in to warm during winter time and Chew up the wiring harness (toyota famous soy based wiring). It was a $1800 repair. Since it was winter time and I don't have warm garage, I bite the bitter bullet and spend the money to get it fix. It was a simple fix, but repairing in freezing cold weather is not fit me.

 

[KLF]

Bravo !!! I actually learn the hardway about this rodent problem on my Sequoia, not LC. Same engine that rodent get in to warm during winter time and Chew up the wiring harness (toyota famous soy based wiring). It was a $1800 repair. Since it was winter time and I don't have warm garage, I bite the bitter bullet and spend the money to get it fix. It was a simple fix, but repairing in freezing cold weather is not fit me.

Toyota doesn't make wire, all manufacturers use soy based insulation. It's a way to get away from petroleum.

$1800 is ridiculous, if it was the same repair. But I hear ya, I no longer work in the bitter cold, and my garage isn't heated.

 

[bloc]

Tesa 51026 is what the German manufacturers use on their harnesses and it is amazing stuff. Black fabric, not vinyl, very heat resistant. Even super 33+ leaves behind a black adhesive residue when subjected to the heat under our hoods. The tesa stuff doesn’t do this at all.

 

[slowride]

FYI...

Toyota Faces Revived Claims That Wiring Parts Drew Rodents
Aug. 20, 2020, 5:45 PM

• Trial court misidentified alleged defect, 9th Cir. says
• Fraud-based claims properly dismissed

Car owners adequately stated claims against Toyota Motor Sales, U.S.A. Inc. over soy-based wiring harnesses allegedly prone to chewing damage from rodents, the Ninth Circuit ruled.
The trial court erred when it dismissed warranty claims on behalf of a multistate proposed class, the appeals court said Wednesday in an unpublished per curiam opinion. And the claims by Albert Heber and other consumers are plausible, the court said.

 

[KLF]

FYI...

Toyota Faces Revived Claims That Wiring Parts Drew Rodents
Aug. 20, 2020, 5:45 PM

• Trial court misidentified alleged defect, 9th Cir. says
• Fraud-based claims properly dismissed

Car owners adequately stated claims against Toyota Motor Sales, U.S.A. Inc. over soy-based wiring harnesses allegedly prone to chewing damage from rodents, the Ninth Circuit ruled.
The trial court erred when it dismissed warranty claims on behalf of a multistate proposed class, the appeals court said Wednesday in an unpublished per curiam opinion. And the claims by Albert Heber and other consumers are plausible, the court said.

got link?

 

[slowride]

Must have standing...

the appeals court said Wednesday in an unpublished per curiam opinion.

 

[KLF]

Must have standing...

the appeals court said Wednesday in an unpublished per curiam opinion.

I have no idea what that means, but I won't hold my breath waiting for a reimbursement check. Interesting info though, thanks.

 

[peez206]

Thank you for this write up!! I unfortunately encountered this on Thanksgiving morning when I was moving the LC from the driveway to the curb to save a visitor a parking spot. It was throwing P033D and after my guests left for the night P032D was added to the list. Sure enough two of the plugs were chewed right off. Had a similar nest of white stuff but on the opposite side under the manifold. Overall it took me about 4 hrs, mostly a bunch of hoses that need to be dealt with. I did have trouble getting the two brackets in the back off but I managed to get one and it allowed me to move the manifold out of the way enough to replace the harness.

Thanks also for the tip in the permanent dtc codes. I guess I'll hit the freeway for a nice long drive tomorrow to get it cleared for good.

Hopefully I don't encounter this again. Parts guy at the dealer said they see this weekly.

Yikes.

 

[Kurosawa]

I also got to spend the greater part of a day dealing with this same issue. It was nice to have the @KLF DIY to help me quickly diagnose the issue and get after it, thanks man

I would say start to finish it was similar to the 4hr job indicated by @peez206 maybe a little more. By and large, an easy job to deal with made partially very frustrating by the largest wire harness clip between the engine and the firewall. That single clip took me nearly an hour to release, I finally got it holding a flat head drill bit between two fingers (no room for a thumb) and blindly wedging it into the correct spot to release the clip which of course has only an inch and half clearance from the firewall and needs to be pushed closer to said firewall to remove. If someone knows a better way please share, it would help bring this down to an easy three-hour job. I followed @KLF in adding more wire loom to the new harness to up-armor it from happening again, I just scavanged off the old one for the loom.

Clip issue aside I'm really happy with the repair and all codes are resolved. I think as cheap and light as that harness is combined with the serious compromise it makes for using the vehicle, I'm just going to get a spare and toss it in with my electrical repair gear. It would really mess up a trip and yet could easily be fixed in the field if you have it with you.

I also ordered some peppermint oil to spray in the engine bay to keep the little bastards out. I don't want to bait them near the truck as I think it's probably a bad idea to attract them to the thing I want them to avoid so this is my solution for now unless someone has another idea.

Before and after pictures.

 

[KLF]

I also got to spend the greater part of a day dealing with this same issue. It was nice to have the @KLF DIY to help me quickly diagnose the issue and get after it, thanks man

I would say start to finish it was similar to the 4hr job indicated by @peez206 maybe a little more. By and large, an easy job to deal with made partially very frustrating by the largest wire harness clip between the engine and the firewall. That single clip took me nearly an hour to release, I finally got it holding a flat head drill bit between two fingers (no room for a thumb) and blindly wedging it into the correct spot to release the clip which of course has only an inch and half clearance from the firewall and needs to be pushed closer to said firewall to remove. If someone knows a better way please share, it would help bring this down to an easy three-hour job. I followed @KLF in adding more wire loom to the new harness to up-armor it from happening again, I just scavanged off the old one for the loom.

Clip issue aside I'm really happy with the repair and all codes are resolved. I think as cheap and light as that harness is combined with the serious compromise it makes for using the vehicle, I'm just going to get a spare and toss it in with my electrical repair gear. It would really mess up a trip and yet could easily be fixed in the field if you have it with you.

I also ordered some peppermint oil to spray in the engine bay to keep the little bastards out. I don't want to bait them near the truck as I think it's probably a bad idea to attract them to the thing I want them to avoid so this is my solution for now unless someone has another idea.

Before and after pictures.

View attachment 2537716

View attachment 2537717

Yeah, I totally hear ya on that clip/connector, it's maddening how difficult it is to get apart. It would be somewhat easier if you could unbolt the bracket to wriggle it out from between those valves, but no.... the stupid connector is in the way of removing the bolt! Of course, my luck I would drop the bolt if I took it out anyway.

I think I used a bent pick to get the clip to release, but it wasn't easy, and I was afraid of breaking something.

 

[Weatherman]

Regrettably, I am now in this club. I believe it was the former owner's doing. Following my purchase, I was doing the basic stuff like oil and filter change, new engine air filter, etc. I cleaned a ton of debris out of the engine bay where leaves fall down from the windshield. In general it was clear the former owner parked outside under lots of trees (and let the dealer do all the maintenance), which is pretty common in DC. When I opened the glove box to replace the cabin air filter (after much rejoicing that the door functioned properly), I discovered a rodent nest behind the recirculation door. I cleared it out, changed the filter, and to my knowledge the bugger never came back. I check it monthly and it has been clean and clear since.

Fast forward 11 months and one global pandemic later, and I get the CEL, blinking 4LO and check VSC waning indicator. The code reader yielded 'knock sensor 4 bank 2' and the CEL and other lights came back immediately after clearing. IH8MUD and Tundra owners have this in common and between the MUD forum and some rando Tundra write ups, I figured it a virtual certainty that I had a rat/harness issue. I ordered the OEM harness, two $10 eBay knock sensors (just in case) and two OEM manifold gaskets. Once I popped off the engine cover, I knew what I would find under the intake - after seeing the snacking that they were doing on the foam bits.

Clearly there were some homesteaders living in my engine bay at one time. This thread saved me the headache and the $ of the dealer maintenance. It took me about 6 hours. It could have been 4.5 but I dropped the right rear bolt and spent an hour locating it plus another half hour making a magnet/clothes hanger tool to retrieve it. The wire harness at the back of the manifold is a PITA. Seems they could have designed that better - like attach it to the firewall, not the manifold.

In case you're reading this, you'll need to do the following (as others before me have said):
1. Remove the DS skid plate and drain off the radiator fluid via the petcock on the bottom rear-facing corner of the DS on the radiator. FWIW - I got about 1.5 gallons out. TIP: It drains much faster with the radiator cap off. You don't need to drain the coolant in the block. Replace (later after re-assembly) with Toyota Pink or comparable per the FSM.
2. While you wait for the radiator to drain, disconnect the negative battery terminal and remove the engine cover. Just lift up on the front edge and rotate it up ~30 degrees and then pull toward you.
3. Follow the steps in the FSM (see KLF's link in post #1 of this thread) to remove the intake manifold. This is easy and very intuitive - it's mostly just removing hoses and wire harnesses. Take some pictures or video before you begin for reference if needed during re-installation. The intake has two attaching points for an unrelated wire harness which runs between the manifold and the firewall. These clips hold the wire bundle in place and the wire loom is thick/rigid so there is no give/play in it. You can't just pull on the manifold to gain more space to release the bundle. Each clamp must be released for the manifold to come all the way out of the vehicle. It is a royal PITA, second only to losing a manifold bolt into the horrible abyss between the firewall and the engine. Take care to hold onto the bolts as you remove them or you will surely drop one like I did. This is followed by much cussing and self-flagellation. use a pick or similar tool (I used a disassembled clothes hangar) to release the harness clamp from the intake mounting tab.
4. Cover the intake pipes with tape.
5. Have a fermented refreshment.
5. Clean the rodent flop house mess up
6. Repair or replace the harness, take time to beef up the new harness where there is nothing but wire showing. I used old bits of wire loom from the old harness as previous members have done.
7. Re-install is pretty much the reverse of removal. Make sure to clean the intake port surfaces before putting the intake back on. Don't attach the wire harness clamps at the back until you are fully satisfied the job is done. I completely re-assembled everything, topped off the coolant, and test drove my truck before re-attaching those clamps.
8. Park in the garage and have another #5.



Cheers
Paul

 

[Whiskerz]

I think I joined this group today. I have the same 3 lights and a knock sensor code. Truck is parked outside since we are in the middle of moving and stuff is in the garage. Looks like I have a new project now.

 

[peez206]

FWIW I've been spraying a mixture of peppermint oil/water around my skids about once a month and it has seem to keep the critters away. Hopefully that is something that works long term since its a pretty cheap prevention step. Especially around this time of the month as we get into winter.