2007 LE 2.4 Knock Sensor
 

I have a Gen 6 2AZ-FE Camry with a knock sensor issue. Got the code after the vehicle sat for a couple of months. I picked up a new sensor prior to tearing into it to save time. After removing intake and pulling the sensor I discovered that some &%$# rodents had chewed the wires off flush with the Knock Sensor connector. They had also chewed the wires back to where they exit the wiring harness. I understand this is not unheard of in Toyota and Honda. As I pulled enough wire back out of the harness to solder the new connector pig tails I found the 2 wires were shielded. I went ahead and soldered the pigtail and put everything back together. I am still getting the 0328 CEL.

Now I am even more confused. Possible reasons that I can come up with:

1) The lack of shielding is creating interference causing the high voltage return. I couldn't find shielded pigtails to the connector and even then would need to tie them in to the existing shielding. Does this require a replacement wiring harness or do they make a repair kit to work around?
2) I assumed the original knock Sensor was good and the issue was the lack of wire to and from. It could also be bad.
3) I believe I attached the new pig tail wires to the correct wire at the harness. The red wire is to the top wire on the connector closest to the connector release tab.

Does anyone know if the shielding is required between the harness and the Knock Sensor connector? Do they make any type of repair wire that is shielded and goes from the connector to the ECU so the wiring harness doesn't have to be replaced? Are the wires in and out of the Knock Sensor connector polarity specific and have to be landed on the specific wire into the harness? Any other possibilities I am missing?

Sorry this is long but I really don't want to have to take this apart and put it back together multiple times to figure it out. Any and all help is greatly appreciated. Thanks,
Miles

P0328
-Open in knock sensor circuit
-Knock sensor
-ECM

The code is for the Bank 1 sensor. Which cyl heads sensor wiring is damaged, front or back?

1) If available, could replace the wiring harness going from the two sensors to where they join up to a single plug. This plug then connects to the harness wiring going to the ECU.

Doubt can solder to the current wiring shielding. Suggest finding copper tape to use a shielding. Then solder a wire to this tape and ground that wire. The sensor shielding grounds to the cyl head as a single point (same ground point as for A/F sensors).

2) The internet has info on testing the sensor. It's a piezoelectric device that acts as a microphone to generate a voltage.

3) For the sensor harness plugs. Terminal 1 is nearest the locking device on the side of the plug. The wiring diagram has the following:

-Bank 1 sensor has white (terminal 1) and black (2) wiring to it.
-Bank 2 sensor green (1) and red (2).

Thanks Toyomoho. I hope I understand this. The sensor is located on the back of the engine in the middle below the intake manifold. From all that I have been able to gather the 2.4 L4 engine in 2007 (2AZ-FE) only had a single flat type knock sensor. The wires in and out are red and green.

I may give the copper tape a try as shielding. I may need to go back a little further in the harness to connect to existing shielding then run to ground. That sounds like it should solve the shielding issue.

I could kick myself for not checking the sensor itself before reinstalling. That old ASSUME thing bit me again.

I feel pretty confident that I got the pigtail wire connected to the same wire in the harness the old one would have been on. I just don't know if it matters which side the voltage is biased on. I may run a continuity check from the sensor connector to the ECU pin if I can determine which one it is. Back to working on it.

Thanks for the help!

You are correct.

Revise previous post info for a V-6 to a 4-cyl as follows:

The sensor red wire is terminal 1, green wire 2.

The wiring harness runs from sensor to ECU without additional connections.

The shielding would run up to the plug. For a reference check the A/F and cam/crank sensor wiring. All are shielded and ground to the same point as the knock sensor.

Thanks Joey,
I got rained out this afternoon. Will look for copper tape in the morning preferably with conductive adhesive and see how it works for substitute shielding. Will also try a continuity check. If I interpret the 0328 code correctly, it indicates an open. Will need to test the entire length of both wires to make sure the little rodents didn't get it somewhere else as well. Will also check the resistance on the knock sensor itself and see if that is part of the issue. Thanks again!

Ign ON, check voltage between terminals 1 and 2 of harness plug disconnected from sensor. Should be 4.5-5.0v.

Knock sensor resistance 120-280k at 68°F.

. I performed the check on the Knock Sensor and it was good. When I pulled everything back apart and was undoing the electrical tape that I wrapped the wires in after the solder and the heat shrink one of the wires came apart. I'm not sure if the solder broke because I left the pig tail too long and the bend stressed it or the routing may have caused it. It could have also been the lack of shielding.

I found a length of wire in the garage that had shielding and removed some of it. Found some copper tape locally but expensive. It was the type with the conductive adhesive. I shortened the pig tails, verified which wire went to the pig tail connections. Pushed the shielding I salvaged up toward the connector along with the heat shrink and soldered the wires. Before going any further I did another voltage check just to make sure the solder connections were good. Pulled the heat shrink down then the shielding but the wire was to fat for the shielding to slip over. Removed the insulation on about 8" of another wire and laid it on top of the existing wire shielding. Started at the wire harness where the Knock Sensor wires came out and started wrapping it with the copper tape. Took the bare wire all the way to the top and continued wrapping the wire with copper tape. Doubles the bare wire over and ran it back down the length of the pigtail and secured it with the copper tape. Soldered it to the outside of the first layer of copper tape at the base and ran it to the ground on the back side of the engine.

Put everything together and it worked. Not sure if it was the wire connection, the shielding or both. CEL went away and it drove with out issue around the block. Decided to take it from Orlando to Tampa and the Knock Sensor was no longer an issue and it was great to get the gas mileage back close to 30 MPG instead of the 15 I had been getting. Then on the way back the power steering started having issues. Power steering was near non existent at slow speed and just a little better at highway speed. By the time I got home the fluid had dumped overflowing from the reservoir. Got the usual squeeling from the pump but not sure why it was coming out the reservoir? Still looking to try to determine exactly what the issue is but leaning toward a pump replacement. Always something. Thanks for the idea on the copper tape. I went by a surplus/salvage store today and was looking through their wire area. I think if I had it to do over again I would have gotten a copper braided sleeve from there for about $1.50/ foot. I think the 5/16 diameter would have worked well and will keep that in mind if needed again for shielding. Thanks again for all your help Joey!. Saved a lot of extra work

Great job! Thanks for the detailed write up.

The PS pump has a pressure valve. If stuck, the fluid may back flow into the reservoir.

Could also be air in the system. Top off reservoir and turn steering wheel from stop to stop a few times.

Check for PS leaks. One area is behind the rack boots for the tie rods.

If the PS fluid is dark or black, try removing and replacing the fluid in the reservoir between drives until its clear again.

Thanks Joey.
Yesterday I had the car on jack stands. Went under and checked for leaks and binding. No leaks that I could find. Topped off the reservoir. Let it run and turned the wheel stop to stop several times. Had a bad squeel. I pulled the connector on the switch and tried to do the resistance check but could never be sure I got a good connection on the switch or connector. Turned up nothing on that. I did notice as I was turning stop to stop with the switch connector off that the squeel quieted down. I reconnected the switch connector and continued the stop to stop turns and though there was little difference with the switch connected and disconnected. I drove it around for about an hour last night and it worked fine.

At this point I think it could be as you say that the fluid level was low and may have gotten an air bubble in the system. Could also be a failing pump or the switch. I will drive it around for a week or two and see if I have any further issues. It wasn't easy to steer when it seemed to fail but not impossible. I will keep a close eye on it over the next couple of weeks to see. One thing I did notice is that the reservoir has a stain line from the Dextron. I am wondering if just a cursory glance at the reservoir to see the level may have been masked by the dark stain. I think I may go ahead and flush the system with fresh Dextron. Just the fresh fluid added seemed to help the ability to see the level. If I had to guess at this point I would be leaning toward the fluid level being low. I have only had this car a few months so learning as I go. Thanks again for the help!

A PS pump failure should still allow manual steering. This being a stronger turning force needed to steer, but steering is still very possible.

Sometimes a pressure relief valve or bypass valve inside the pump sticks. The result is more difficult steering as if something is resisting the steering wheel movement.

Pump squealing is never a good sign. Assumed you checked the PS belt for proper tension and condition.

There is a filter screen inside the reservoir. When investigating determine if the screen is clear of debris.

The switch runs to the computer. The switch tells it if there is demand for steering (based on fluid pressure) and if so to increase engine rpm.