2003 Tundra Knock sensor condenser

Rodents got to the knock sensor wiring and plastic knock sensor connector. Took off intake, replaced offending knock sensor and wire (soldered into harness), reassembled. Literally as I was attaching the last bolt I noticed a small connector taped to the engine harness. The wires entering the connector had be chewed off. After much research I determined the device to be the “knock sensor condenser”. I can not locate the wires that run to the connector so I have no idea how to reconnect the condenser. I went to two Toyota dealers and they do not know either. Any help would be appreciated. I need to pass annual auto inspection and I can’t with a code P0325. Thanks

 

Knock sensor condenser?

Can you please provide links to the resources that helped you determine this?

If it was taped off to begin with, seems (whatever it was "for") was not deemed necessary.

 

Where was the connector? You got a picture of it? I had to replace my knock sensor harness and didn't see any extra connectors.

 

Is this a V6 or V8?

I can't seem to copy the diagram from Alldata, but it shows 2 Knock Sensors in the valley, and that's it. No other wiring.

For the V8 the code P0325 is related to the left bank sensor not having a signal between 1700 and 5400 rpm.

For the V6, it's looking for a signal between 1500 and 5500 RPM.

 

First thanks. It was not “taped-off”. It was literally attached to the main engine harness on the firewall with two wraps of electrician tape. In other words behind the engine, in front of the firewall at the same level as the starter. It is located beyond the top of the picture (out of frame).

I determined what it was by removing it from the harness (easy since the two wires going to the condenser were chewed off) and Googling the part number 90980-04083. It is a noise filter. The dealer immediately recognized it as the “radio condenser” after which they determined it was actually the knock sensor condenser. They had no idea where it connected - harness? Grey box by starter? Or what color wires it should connect to.

 

Sorry 4.7l v8

 

There are two knock sensors in the valley one on each bank - they are one wire knock sensors (round).

 

I was going to mention the noise filter, but forgot to add it to my post. Its located on the right side of the engine bay, so its odd that the wiring would have been near the engine valley. I would make sure both of your knock sensor wiring looms are damage free and ensure the connector is secure on the sensor.

**edit** I didnt see the info you posted about the harness behind and above the Back of the engine. Yes, the noise suppressor wiring goes through there, but I'm not so sure about its involvement with the knock sensors. I'll have to look at the wiring diagram and see what I can learn..

 

I will certainly do that when I tear it apart again but from what I have read this condenser could be the reason I am throwing a code.

 

I have partially disassembled the connector. One of the wires appears to be black with a red stripe if that helps on the wiring diragram.

 

Heres a couple of sections of the wiring harness. 1st one shows the noise filter, which gets power through the ignition switch, and shares power through the ignition coils. That wire is Black and Red, which would be the one you found.



The second grab shows the knock sensors which share a ground with the O2 sensors. Those wires are grey and brown and black and brown.



Unfortunately the shot is sideways, so the knock sensor diagram starts on the right side of the picture. Those go right to the ECU.

that code you are triggering is only associated with the left bank knock sensor, so your problem lies within that KS wiring.

hope this helps...

 

First and foremost thank you very much for the diagrams. If I understand what I can see of the diagram the noise filter attenuates certain frequencies that are generated by the ignition coils - nothing to do with the knock sensor. I see the grey and black leads from knock sensor 1 and 2 going to the engine control module. Since the knock sensors are 1-wire I believe the ground is provided by the physical connection between the sensor and the block so I don't see how they "share a ground". If they did I could understand how the condenser affected the knock sensor circuit. What am I missing?

I also see the black/red stripe from the condenser going to the pin labeled SLT+ (don't know what that is according to Google it is the "Electrical Shift Solenoid Valve SLT") on the engine control module pin-out. I could open up the main engine harness and look for a chewed brown wire.

Yesterday I spent the day chasing down a P0420 code (bad cat) even though the engine runs smoothly. Replace upstream and downstream O@ sensors no change in code. I have ordered a wifi OBDII reader and software - should be in Saturday.

Today - truck won't start. Battery voltage 12.8v. Turn key, hear click in engine compartment or under dash, dash lights flash. Made an appointment for Aug 10 at repair shop - earliest available. But I would like to get this thing running and inspected before then. Any ideas?

Thanks

 

You are correct, The Knock sensors are single wire, so the "shared" ground is the block. I was looking at the brown wire which goes to the EEC.

The Red/Black wire goes directly from the noise suppressor to a Junction Block under the dash, which is tied into the injectors as well. It appears to be switched power through the ignition switch. (see illustration)






I don't see the SLT connection in the diagram, so I'm not sure where you're seeing that.

Unfortunately, the P0420 code can be a catch all if the engine is not performing at 100%. If anything is causing the A/F ratio to be incorrect, and the O2 sensor is reacting negatively, the EEC could possibly read that as a problem with the O2 sensor.

Your original problem with the knock sensor really should be repaired first, before diving into the rabbit hole.

 

Ok, I found the SLT wire you mentioned. Yes, that is a separate circuit that goes between the EEC and the Trans Solenoid.

Totally different system.

 

Did you bump or loosen anything on the starter?

 

Excellent thought..

 

I’d check and clean and dielectric grease my grounds behind the engine block. There is one main ground and and smaller ECU one adjacent on the pass side between the firewall. There is another ECU one on the drivers side between firewall. The other main ground is at the battery to quarter panel. Give yourself a couple of hours to do this as you’ll be reaching and going by feel. The pass side grounding bracket is fun fun fun.

 

First thank you everyone for your time and consideration.
1. I did not touch, loosen or tighten anything on the starter or on the grey connection box next to the starter
2. I agree I need to fix the knock sensor code first.
3. New symptom starter will not engage - just a bunch of clicking not like a solenoid but more like a contact. Battery voltage 12.8 alternator 13.4v.
4. Next day - without any attempts to fix anything - truck started. I drove it to a repair shop that has "an award winning Toyota mechanic" whatever that is.
5. Called the insurance company and filed a claim under comprehensive (I didn't know that they covered such things but some do apparently)

I will gladly pay the deductible when they fix it.

I will definitely report what they found and did to repair it.

Again, thank you! I had no one else and you all helped graciously and without the normal "chest beating" I have seen on other forums.

Bob

 

Just speaking for myself, I know how it is to be the new guy on a forum. Nobody likes to be berated when you don't know the answer... I sincerely hope this works out in your favor Bob, Never thought about using Comprehensive for this. Feel free to ask about any other concerns and we are looking forward to hearing an update

 

It may be that your starter coincidentally crapped out at the same time. It could also be that your battery reads ok, but isn't actually putting out the amps the starter needs. Or corrosion on the connections between here and there.

 

Best of luck. Could have some chewed wires in other less observable locations. Chewed wires could have shorted and caused other problems in the electrical system. Starters on these are pretty bullet proof. Replaced the contacts on mine at 120k miles or so and haven't had any trouble since. The Toyota tech I talked to in the service dept to buy the contacts said in 20 years he's never had to replace the whole starter. The pain in the ass location in the valley protects it from heat and prolongs the life.

 

Did you replace yours for preventative maintenance? Mines at 171k miles with not a problem since new. Its the Heavy Duty 2.0kw ‘Cold Package’ Starter. Cheaper than the others and can be swapped in place as an upgrade.

I might do this contacts swap soon, but wonder if there are other items needed swapping in there. $112 bucks might be a no brainer just to fully replace.

 

Still have my original starter. I've only replaced the contacts inside the starter at around 120k miles or so. Just started clicking instead of engaging the starter. $13. And new intake manifold gaskets, $100. Ouch.

 

Hi Everyone,

Here is how it all worked out (or didn't). The shop I took it to found another chewed through wire in the knock sensor circuit hidden in the main wiring harness and fixed it. This fixed the knock sensor code. Cost $1100 - ridiculous but I only paid $250 deductible on comprehensive - still ridiculous.

They could find nothing wrong with the starter - so they didn't do anything. I guess the "award winning" Toyota tech didn't think about the starter contacts. I didn't know that the solenoid had replaceable contacts or I would have had them replace them when they were in there - looks like I will be taking it apart again to fix starter. Not fun in 94 degrees and 100% humidity - welcome to my life.

4 wheel Hi lite flashing now. I checked transfer case actuator - everything looked great. Had them back probe it and confirmed reference voltage and signals to hi and low switch on transfer case. Found the front axles were engaged, just the axle not to the transfer case. I looks like I will be trying to get the front diff add out - any suggestions?

They reconnected the condenser - black with red strip to ignition coil side and other wire (black with brown I think) to ground. I do not think that this was a factor in any of my problems. Probably just affects the radio that I never listen to - I'm 72 years old and don't like modern music much.

I think that is all - until I get into the front diff add.

Thanks again for all of the help.

Bob

 

Bob:
I’ve posted about the actuators in another thread. I just went through this with the rebuild of my Limited. It’s possible the 2 actuators somehow got out of Sync with each other. If the transfer case actuator doesn’t see the ADD actuator in the correct position, it won’t engage.
While engaging 4Hi, you should hear 2 distinct motors operating. One for each actuator. XFR case first and then the ADD actuator
Beyond that, the diagnostic work will take you inside the actuators looking for corrosion on the contacts or a frozen motor.