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Returnable until Jan 31, 2025
To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.
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Availability:
In Stock.
Arrives
Thursday, Sep 25
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Features
- Sends signals to the engine control module (ECM) to adjust timing
- Helps prevent damage to the engine caused by pre-ignition
- GM-recommended replacement part for your GM vehicle's original factory component
- Offering the quality, reliability, and durability of GM OE
- Manufactured to GM OE specification for fit, form, and function
Description
ACDelco GM Original Equipment Ignition Knock (Detonation) Sensors monitor the engine for pinging or spark knock, and are GM-recommended replacements for your vehicle's original components. These sensors create a voltage signal based on the vibrations caused by erratic air/fuel mixture combustion; the engine control module uses these signals to adjust the ignition timing and air/fuel mixture. These original equipment ignition knock sensors have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.
Brand: ACDelco
Item dimensions L x W x H: 2.7 x 2.7 x 2.3 inches
Item Weight: 2.88 ounces
Style: Modern
Mounting Type: Flange Mount
UPC: 707773013601
Global Trade Identification Number: 01
Manufacturer: ACDelco
Brand Name: ACDelco
Model Number: 213-3521
Mounting Type: Flange Mount
Specific Uses For Product: engine protection and performance optimization in GM vehicles
Item Weight: 2.88 ounces
Item Dimensions: 2.7 x 2.7 x 2.3 inches
Style Name: Modern
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Thursday, Sep 25
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
I had to rework my heads, while I was at it these knock sensors had been an issue for a while. Its a nasty mess down in the knock sensor holes, apparently moisture is an issue. I cleaned the area and installed these knock sensors, the hard part was deciding based on the reviews which sensors to go with. These are OEM, good quality, and have not given any trouble. It helps to thoroughly clean the ports, install new seals, teflon tape the threads, assure the harness and connections are properly routed and well connected. I have found no issue with this product and am well satisfied.
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Reviewed in the United States on June 8, 2023 by GmcSierra15005.3 GmcSierra15005.3
If you have a knock sensor code use these sensors with wiring harness pn 12601822. Order intake gaskets from felpro as well. Also, while the intake is off there is a chance your steam port tubes could be pretty rotted. It’s always good to have them on hand and change them.
Reviewed in the United States on October 19, 2024 by jake
Month later the engine power reduction has been fixed.
Reviewed in the United States on October 31, 2024 by Fred Reza
I had never heard of a knock sensor before getting the error code from my local AutoZone. I found a couple videos and tutorials online that show you how to change them and it seemed easy enough. The first time I did it I over torqued the knock sensors because I didn't read the torque wrench instructions (I know they were over torqued because I accidentally sheared one of the intake manifold bolts with the same torque wrench). After driving around the knock sensor code came back. Not knowing what the problem was, I went to AutoZone and bought another set of knock sensors, which turned out to be the same as these but cost double the price. I bought a replacement manifold bolt on ebay and proceeded to remove the knock sensors. I checked the Ohm reading on them and they check out at 100k Ohms each as specified, they seemed to not be damaged from my over torquing so I tried reinstalling them at the proper torque rating (15 ft-lbs) and the check engine light hasn't come back. So I can take back the ones I bought from AutoZone since these ones worked once I installed them properly. I recommend doing your research and taking your time, there are lots of little things like clips and bolts that can break or get lost.
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Reviewed in the United States on October 1, 2019 by jgardener
These sensors did not work in my 04 avalanche 5.3. I bought a pair to replace a rusted out one and went to torque to the 15ft lbs and the top of both sensors spun on me. I tried them anyway and a few miles down the road while watching DTC's, immediately got codes for both sensors. Did a return and replace, got the new set in, same thing. The top spun before it could even be torqued and yet again, a few miles and the codes set again. Bought another pair of ACDelco's from the AZ, this time these torqued fine without the top spinning. Put everything back together thinking I was golden, nope... a few miles down the road again and the codes set. I then bought the cheapest sensors I can get cause at this point I have nothing to lose other then time, however, these gave the same result as the first two sets. Went to the AZ and got their house brand ones and lone behold, these actually work! I've gone 500miles and no DTC and the diagnostic tests actually passed this time. For grins and giggles, I tested the sensors with a oscilloscope multi-meter to look at the AC sine wave and test the resistance. The 3 sets of ACDelco's produced no AC sinewave but resistance was good. The cheap ones produced more AC than the ACDelco's but resistance was around 50k. I got a third sensor, the house brand, from the AZ and I got spikes of AC of around 5V which was a thousand times better than the other sensors and resistance was smack dab 100k. All it cost me was trying 5 sets of sensors and a lot of headache taking the plenum off and on but it comes to show that don't trust just the resistance of these sensors...thats only showing half the picture. Get yourself a cheap oscilloscope multi-meter and test them before you put them in to save yourself the headache. Also I am either bad at the automotive lottery or theres a bad batch of ACDelco sensors out but in the end I am very quick at swapping these out now.
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Reviewed in the United States on April 2, 2024 by Jimmie Taylor
This review is more to respond to the other reviews I have read about this. This repair is a money maker for GM dealers. It is super easy in comparison to how intimidating the job is. I read some review that said it should take a whole day. It is a 2 hour job unless you take a nap mid way through. Also, the gasket on the intake is completely reusable silicone which clips on the completely plastic intake manifold. DON'T BUY THE GASKET. There is a reason why the stupid gasket is almost $100, it's because it is high quality and reusable. The harness is also probably fine. I should also mention that I am not a super cheap person who would waste tons of time to save a couple bucks. Some of the reviews I read were just ridiculous. To perform this task you just need to peel all the wires and hoses off the intake and zip tie them up to the wiper blade, and pull the intake out from underneath. The gasket is clipped on to the plastic intake. Vacuum out the crap that is in the valley, clean it up, swap the knock sensors and slide the intake back on. The screws on the intake are delightfully captive to the assembly making re-assembly easy. Also to note is how the screw (little M6 things) have plastic boots where they go through the intake. These are also gasket surfaces, as they pass through the intake inside of the base gasket, but for some reason the reusable gasket reflexive replacing people seem to not identify this. Just because it is a gasket doesn't mean you have to replace it. Save the money, buy both sensors (even if you only need one) and nothing else. Have a shop vac on hand and a can of brake cleaner to clean up the gasket surfaces. Once you complete this job, doing it again is super easy should you ever have to.
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Reviewed in the United States on June 17, 2019 by M