Where is the knock sensor located and How to remove and install on Mazda 3?

The location of the knock sensor is in the front side of the block and at the back of the runners of the intake manifold. The first step would be to take off the battery cover and unplug the cable in the negative battery terminal. The intake manifold should be removed next. You can then disconnect the electrical connector to the knock sensor followed by removing the bolt of the knock sensor and removing the knock sensor. To install it, repeat the steps of removing it and tighten the knock sensor bolt to the required tightness.

How to replace the knock sensor on Mazda 6?

In four-cylinder models, the knock sensor is on the front of the block, behind the bunds of the intake manifold. Starting with taking out the cable on the negative battery terminal and then take out the intake manifold. The second step includes disconnecting the electrical connector connected to the knock sensor, retaining bolt, and knock sensor. Installation is the opposite of removing, in making sure that the retaining bolt is snug according to the required torque. To check the V6 3.0L models, the first step is to disconnect the negative battery terminal, lift the vehicle safely on jackstands, and take off the engine compartment under cover. Unfit the electrical connector of the knock sensor, remove the retaining bolt and remove the knock sensor and then repeat the steps of the operation by reversing the steps and fitting the bolt back again with the required torque. In 3.7L models, where there are two knock sensors in the valley between the cylinder heads, disconnect the electrical connections of the knock sensors and remove the retaining bolts that hold the sensors. The process of reinstallation is in reverse order and the retaining bolts are tightened to the required torque.

Genuine Mazda Knock Sensor

Engine Knock Sensor

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26 Knock Sensors found

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Mazda Knock Sensor Part Number: LF01-18-921
$48.14 MSRP: $64.19
You Save: $16.05 (25%)
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Product Specifications
- Other Name: Sensor, Knock
- Replaces: 1F20-18-921A, 1F20-18-921
Fits the following Mazda Models:
- 3 | 2010-2013, 2004-2006 | i, S, SP23 | 4 Cyl 2.0 L GAS, 4 Cyl 2.3 L GAS, 4 Cyl 2.5 L GAS
- 5 | 2012-2015, 2006-2007 | Grand Touring, Sport, Touring | 4 Cyl 2.3 L GAS, 4 Cyl 2.5 L GAS
- 6 | 2003-2013 | i, Mazdaspeed, S | 4 Cyl 2.3 L GAS, 4 Cyl 2.5 L GAS, 6 Cyl 3.0 L GAS
- B2300 | 2001-2009 | Base, SE, SX | 4 Cyl 2.3 L GAS
- CX-7 | 2010-2012 | Sport, SV, Touring | 4 Cyl 2.5 L GAS
- MX-5 Miata | 2006-2015 | 25th Anniversary Edition, Base, Club, Club Spec, Grand Touring, Special Edition, Sport, SV, Touring | 4 Cyl 2.0 L GAS
- Tribute | 2008-2011, 2005-2006 | Hybrid, i, S | 4 Cyl 2.3 L FULL HYBRID EV-GAS (FHEV), 4 Cyl 2.3 L GAS, 4 Cyl 2.5 L FULL HYBRID EV-GAS (FHEV), 4 Cyl 2.5 L GAS, 6 Cyl 3.0 L FLEX, 6 Cyl 3.0 L GAS
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Mazda Knock Sensor Part Number: PE01-18-921
$62.38 MSRP: $83.18
You Save: $20.80 (26%)
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- 3 | 2012-2018 | Grand Touring, i, i Grand Touring, I Sport, i SV, I Touring, Mazdaspeed, S, s Grand Touring, s Touring, Sport, Touring | 4 Cyl 2.0 L GAS, 4 Cyl 2.3 L GAS, 4 Cyl 2.5 L GAS
- 6 | 2014-2017 | Grand Touring, Sport, Touring | 4 Cyl 2.5 L GAS
- CX-3 | 2016-2018 | Grand Touring, Sport, Touring | 4 Cyl 2.0 L GAS
- CX-5 | 2013-2018 | Grand Select, Grand Touring, Sport, Touring | 4 Cyl 2.0 L GAS, 4 Cyl 2.5 L GAS
- MX-5 Miata | 2016-2018 | Club, Grand Touring, RF Club, RF Grand Touring, Sport | 4 Cyl 2.0 L GAS
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Mazda Knock Sensor Part Number: P31E-18-921
$93.71 MSRP: $124.98
You Save: $31.27 (26%)
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Product Specifications
- Other Name: Sensor, Knock
- Replaces: P32E-18-921
Fits the following Mazda Models:
- 3 | 2019-2024 | 2.0, 2.5 Carbon Turbo, 2.5 S, 2.5 Turbo, 2.5 Turbo Premium Plus, Base, Carbon Edition, Preferred, Premium, Select, Select Sport | 4 Cyl 2.0 L GAS, 4 Cyl 2.5 L GAS
- 6 | 2018-2021 | Carbon Edition, Grand Touring, Grand Touring Reserve, Signature, Sport, Touring | 4 Cyl 2.5 L GAS
- CX-3 | 2019-2021 | Grand Touring, Sport, Touring | 4 Cyl 2.0 L GAS
- CX-30 | 2020-2023 | 2.5 S, 2.5 S Carbon Edition, 2.5 Turbo, Base, Preferred, Premium, Select | 4 Cyl 2.5 L GAS
- CX-5 | 2019-2024 | 2.5 S, 2.5 S Carbon Edition, 2.5 Turbo, 2.5 Turbo Signature, Carbon Edition, Carbon Edition Turbo, Grand Touring, Grand Touring Reserve, Signature, Sport, Touring | 4 Cyl 2.5 L GAS
- CX-50 | 2023-2024 | 2.5 S, 2.5 Turbo | 4 Cyl 2.5 L GAS
- CX-9 | 2016-2023 | Carbon Edition, Grand Touring, Signature, Sport, Touring, Touring Plus | 4 Cyl 2.5 L GAS
- MX-5 Miata | 2019-2023 | 100th Anniversary Special Edition, Club, Grand Touring, RF 100th Anniversary Special Edition, RF Club, RF Grand Touring, Sport | 4 Cyl 2.0 L GAS
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Mazda Knock Sensor Part Number: LF02-18-921
$95.44 MSRP: $127.28
You Save: $31.84 (26%)
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- 3 | 2007-2013 | i, Mazdaspeed, S | 4 Cyl 2.0 L GAS, 4 Cyl 2.3 L GAS
- 5 | 2008-2010 | Grand Touring, Sport, Touring | 4 Cyl 2.3 L GAS
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Mazda Knock Sensor Part Number: N3H1-18-921A
$109.54 MSRP: $146.07
You Save: $36.53 (26%)
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Product Specifications
- Other Name: Sensor, Knock
- Replaces: N3H1-18-921
Fits the following Mazda Models:
- RX-8 | 2004-2011 | 40th Anniversary Edition, Base, Grand Touring, R3, Shinka, Sport, Touring | 2 Cyl 1.3 L GAS
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Mazda Knock Sensor Part Number: L807-18-921
$114.39 MSRP: $152.54
You Save: $38.15 (26%)
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- 3 | 2007-2013 | Mazdaspeed, S | 4 Cyl 2.3 L GAS
- 6 | 2006-2007 | i, Mazdaspeed, S | 4 Cyl 2.3 L GAS, 6 Cyl 3.0 L GAS
- CX-7 | 2007-2012 | Grand Touring, Sport, Touring | 4 Cyl 2.3 L GAS
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Mazda Knock Sensor Part Number: GY01-18-921C
$174.33 MSRP: $232.48
You Save: $58.15 (26%)
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- MPV | 2000-2001 | DX, ES, LX | 6 Cyl 2.5 L GAS
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Mazda Knock Sensor Part Number: GY02-18-921A
$180.35 MSRP: $240.51
You Save: $60.16 (26%)
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Product Specifications
- Other Name: Sensor, Knock (Mpvm)
- Replaces: GY02-18-921
Fits the following Mazda Models:
- MPV | 2002-2006 | ES, LX, LX-SV | 6 Cyl 3.0 L GAS
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Mazda Knock Sensor Part Number: 1F21-18-921
$19.38 MSRP: $44.01
You Save: $24.63 (56%)
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- B3000 | 2004-2007 | Base, DS, SE | 6 Cyl 3.0 L GAS
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Mazda Knock Sensor Part Number: KJ01-18-921A
$185.33 MSRP: $247.15
You Save: $61.82 (26%)
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- Millenia | 1995-2002 | Base, Millennium Edition, S | 6 Cyl 2.3 L GAS
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Mazda Knock Sensor Part Number: FP39-18-921
$192.49 MSRP: $256.71
You Save: $64.22 (26%)
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Product Specifications
- Replaces: FSD7-18-921C
Fits the following Mazda Models:
- 626 | 1998-2002 | DX, ES, LX | 4 Cyl 2.0 L GAS
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Mazda Knock Sensor Part Number: KL01-18-921B
$207.55 MSRP: $276.80
You Save: $69.25 (26%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Sensor
Fits the following Mazda Models:
- 626 | 1993-2002 | DX, ES, LX | 4 Cyl 2.0 L GAS, 6 Cyl 2.5 L GAS
- MX-3 | 1992-1995 | Base, GS, SE | 4 Cyl 1.6 L GAS, 6 Cyl 1.8 L GAS
- MX-6 | 1993-1997 | Base, LS, M Edition | 4 Cyl 2.0 L GAS, 6 Cyl 2.5 L GAS
- Millenia | 1995-1996 | Base, L | 6 Cyl 2.5 L GAS
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Mazda Knock Sensor Part Number: JEB3-18-921A
$238.85 MSRP: $318.53
You Save: $79.68 (26%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- Miata | 1999-2005 | 10th Anniversary, Base, LS, Mazdaspeed, SE, Shinsen | 4 Cyl 1.8 L GAS
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Mazda Knock Sensor Part Number: N3A1-18-921A
$325.14 MSRP: $433.60
You Save: $108.46 (26%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Sensor
- Replaces: N3A1-18-921
Fits the following Mazda Models:
- RX-7 | 1993-1995 | Base, R1, R2, Touring | 2 Cyl 1.3 L GAS
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Mazda Knock Sensor Part Number: 1F22-18-921
$11.00 MSRP: $14.44
You Save: $3.44 (24%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- B4000 | 2004-2009 | Base, DS, SE | 6 Cyl 4.0 L GAS
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Mazda Knock Sensor Part Number: JE49-18-921A
$53.77 MSRP: $70.58
You Save: $16.81 (24%)
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Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- 929 | 1992-1993 | Base | 6 Cyl 3.0 L GAS
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Mazda Knock Sensor Part Number: FS7N-18-921A
Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- Protege | 2001-2003 | DX, ES, LX, Mazdaspeed, MP3 | 4 Cyl 2.0 L GAS
- Protege5 | 2002-2003 | Base | 4 Cyl 2.0 L GAS
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Mazda Knock Sensor Part Number: AJ03-18-921A
Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- Tribute | 2001-2006 | DX, ES, LX, S | 6 Cyl 3.0 L GAS
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Mazda Knock Sensor Part Number: AJ57-18-921A
Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- 6 | 2003-2008 | i, Mazdaspeed, S | 4 Cyl 2.3 L GAS, 6 Cyl 3.0 L GAS
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Mazda Knock Sensor Part Number: CY01-18-921
Product Specifications
- Other Name: Sensor, Knock
Fits the following Mazda Models:
- 6 | 2009-2013 | S | 6 Cyl 3.7 L GAS
- CX-9 | 2007-2015 | Grand Touring, Sport, Touring | 6 Cyl 3.5 L GAS, 6 Cyl 3.7 L GAS

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Mazda Knock Sensor

Mazda Knock Sensor actively detects engine knock and allows the control unit to fine-tune ignition timing to maintain performance and reliability as the driver enjoys smooth power. The Knock Sensor uses a piezoelectric element to convert tough vibration into rapid electrical signals that allow for instant timing and boost adjustments that halt detonation before it causes any harm to the engine. By protecting against the knock phenomenon, Mazda engines ensure brisk acceleration on regular fuel, fuel economy, and engine longevity during heat or high-altitude conditions. Alongside this unseen protector, Mazda gets drivers excited with Skyactiv powertrains that sip fuel but surge forward, Kodo design that looks in motion even when parked, and i-Activsense features such as radar cruise and lane keep to add confidence but not take control away. Mazda is also investing in electric assistance and mild hybrids for cleaner drives, and its i-Activ AWD system puts itself through its paces on rough tracks to ensure that weekend adventures still remain fun. Lightweight construction, sharp steering, and comfortable cabins make every Mazda feel like a little road tripper, with every errand turning into a mini road trip. Because the identical Knock Sensor strategy is integrated across the entire range, each Mazda model has automatic engine defense working every second to ensure owners focus on the pleasure of driving. Together, advanced safety, clever efficiency, and engaging dynamics are why the brand continues to win hearts worldwide.

You'll get great performance and real durability when you pick genuine OEM Knock Sensor. Mazda builds these using high-quality materials and official factory methods to ensure they hold up mile after mile. You deserve that Mazda reliability without the headache of cheap knockoffs. It is easy to find exactly what you need in our huge inventory of genuine parts. Plus, every OEM part carries a real manufacturer's warranty for your peace of mind. You will love our low prices too. Order today and we will ship your brand-new parts fast. They often reach your door in just a few days.

Mazda Knock Sensor Parts and Q&A

Knock Sensor
LF02-18-921
Q: Where is the knock sensor located and How to remove and install on Mazda 3?
A:
The location of the knock sensor is in the front side of the block and at the back of the runners of the intake manifold. The first step would be to take off the battery cover and unplug the cable in the negative battery terminal. The intake manifold should be removed next. You can then disconnect the electrical connector to the knock sensor followed by removing the bolt of the knock sensor and removing the knock sensor. To install it, repeat the steps of removing it and tighten the knock sensor bolt to the required tightness.
Knock Sensor
L807-18-921
Q: How to replace the knock sensor on Mazda 6?
A:
In four-cylinder models, the knock sensor is on the front of the block, behind the bunds of the intake manifold. Starting with taking out the cable on the negative battery terminal and then take out the intake manifold. The second step includes disconnecting the electrical connector connected to the knock sensor, retaining bolt, and knock sensor. Installation is the opposite of removing, in making sure that the retaining bolt is snug according to the required torque. To check the V6 3.0L models, the first step is to disconnect the negative battery terminal, lift the vehicle safely on jackstands, and take off the engine compartment under cover. Unfit the electrical connector of the knock sensor, remove the retaining bolt and remove the knock sensor and then repeat the steps of the operation by reversing the steps and fitting the bolt back again with the required torque. In 3.7L models, where there are two knock sensors in the valley between the cylinder heads, disconnect the electrical connections of the knock sensors and remove the retaining bolts that hold the sensors. The process of reinstallation is in reverse order and the retaining bolts are tightened to the required torque.