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GM 21024981 Sensor Assembly, Knock

2000-2005 GM

Customer Questions & Expert Answers (14)
GM 21024981 Sensor Assembly, Knock
  • Part Description
    SENSOR, Distributor (also Knock Sensor)
  • Replaced By
    19434673
  • Replaces
    21024729
  • Manufacturer
    General Motors
Make sure this part fits
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  • Related Parts
  • Product Specifications
  • Vehicle Fitment
  • Customer Questions & Expert Answers
  • Product Specifications

    BrandGenuine GM
    Manufacturer Part Number21024981
    Part DescriptionSENSOR, Distributor (also Knock Sensor)
    Other NamesKnock Sensor
    Item Dimensions2.0 x 2.1 x 1.1 inches
    Item Weight0.40 Pounds
    ConditionNew
    Fitment TypeDirect Replacement
    Replaces21024729
    ManufacturerGeneral Motors
    SKU21024981
    WarrantyThis genuine GM part is guaranteed by GM's factory warranty.
    Shipping & ReturnShipping Policy Return Policy
    Warning: California's Proposition 65
  • Vehicle Fitment

    Year Make Model Engine Important vehicle option details
    2000-2002 Cadillac Deville8 Cyl 4.6LDEVILLE, HIGH LUXURY, SEVILLE, SLS, STS, TOURING 4 DOOR
    2000-2002 Cadillac Eldorado8 Cyl 4.6LELDORADO
    2000-2002 Cadillac Seville8 Cyl 4.6LDEVILLE, HIGH LUXURY, SEVILLE, SLS, STS, TOURING 4 DOOR
    2001-2005 Chevrolet Astro6 Cyl 4.3LVAN ASTRO
    2001-2005 Chevrolet Blazer6 Cyl 4.3L2 DOOR, 4 DOOR
    2001-2005 Chevrolet Express6 Cyl 4.3L1 TON CARGO EXPRESS, 1 TON COMMERCIAL/RECREATIONAL VEHICLE EXPRESS, 1 TON PASSENGER, 1/2 TON CARGO EXPRESS, 1/2 TON PASSENGER EXPRESS, 3/4 TON CARGO EXPRESS, 3/4 TON PASSENGER EXPRESS
    2001-2004 Chevrolet S106 Cyl 4.3LCREW CAB, PICKUP, PICKUP EXTENDED CAB
    2001-2004 Chevrolet Silverado6 Cyl 4.3L1500 EXTENDED CAB LONG BOX, 1500 EXTENDED CAB STANDARD BOX, 1500 REGULAR CAB LONG BOX, 1500 REGULAR CAB STANDARD BOX
    2001-2004 Chevrolet Suburban1500 EXTENDED CAB LONG BOX, 1500 EXTENDED CAB STANDARD BOX, 1500 REGULAR CAB LONG BOX, 1500 REGULAR CAB STANDARD BOX, CLASSIC 1500 EXTENDED CAB LONG BOX, CLASSIC 1500 EXTENDED CAB STANDARD BOX, CLASSIC 1500 REGULAR CAB LONG BOX, CLASSIC 1500 REGULAR CAB STANDARD BOX
    2001 GMC Jimmy6 Cyl 4.3L2 DOOR, 4 DOOR
    View More
  • Customer Questions & Expert Answers

    Q:
    I would like to confirm if this is the correct part number for my vehicle. Please advise. Thank you. Posted by GMPartsGiant Specialist
    A:
    You can Select Your Vehicle to check if 21024981 fits your vehicle.
    Posted by GMPartsGiant Specialist
    Q:
    Where is the knock sensor located and how do you access it on Cadillac DeVille? Posted by Customer
    A:
    Beneath the intake manifold, on the inner wall of the back side of the cylinder head, lies the knock sensor. To get to it, you will have to take off or remove and Intake Manifold. Remove the manifold and unplug the knock sensor electrical connector. Unplug the connector to unscrew it from a Knock Sensor. When installing this sensor follow same steps but in a reverse order. Torque tighten your knock sensor properly.
    Posted by GMPartsGiant Specialist
    Q:
    How to check and replace Camshaft Position Sensor,Coolant Temperature Sensor,Crankshaft Position Sensor,Intake Manifold Temperature Sensor,Knock Sensor,Oxygen Sensor,Vehicle Speed Sensor,Neutral Safety Switch,MAP Sensor and Throttle Position Sensor on Chevrolet Blazer? Posted by Customer
    A:
    Various engine sensors and components have checking procedures,the engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature, and a failure in the circuit can cause trouble codes. The resistance should be measured when cold and warm while ensuring reference voltage from PCM is around 5.0 volts for the verification. Manifold Absolute Pressure (MAP) Sensor monitors changes in intake manifold pressure then varies its voltage output accordingly. Look at the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes. Intake Air Temperature (IAT) Sensor acts as a thermistor where you can measure its resistance at different temperatures to make sure it changes as expected. Also, use a scan tool to monitor the IAT sensor for performance. The oxygen sensor in exhaust detects oxygen content which you can check its millivolt signal while warming up your engine. Check whether the oxygen sensor heater has correct voltage or not. Vehicle Speed Sensor (VSS) provides speed data to PCM which can be checked for reference voltage. Depending on the type of engine, Camshaft Sensor and Crankshaft Sensor should be checked for resistance and proper signal output. Finally, Knock Sensors detect engine knock which should be checked for reference voltage and resistance. If any component fails these checks, replacement may be necessary.
    Posted by GMPartsGiant Specialist
    Q:
    How to check and replace Camshaft Position Sensor,Coolant Temperature Sensor,Crankshaft Position Sensor,Intake Manifold Temperature Sensor,Knock Sensor,Oxygen Sensor,Vehicle Speed Sensor,Neutral Safety Switch,MAP Sensor and Throttle Position Sensor on Chevrolet S10? Posted by Customer
    A:
    Various engine sensors and components have checking procedures,the engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature, and a failure in the circuit can cause trouble codes. The resistance should be measured when cold and warm while ensuring reference voltage from PCM is around 5.0 volts for the verification. Manifold Absolute Pressure (MAP) Sensor monitors changes in intake manifold pressure then varies its voltage output accordingly. Look at the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes. Intake Air Temperature (IAT) Sensor acts as a thermistor where you can measure its resistance at different temperatures to make sure it changes as expected. Also, use a scan tool to monitor the IAT sensor for performance. The oxygen sensor in exhaust detects oxygen content which you can check its millivolt signal while warming up your engine. Check whether the oxygen sensor heater has correct voltage or not. Vehicle Speed Sensor (VSS) provides speed data to PCM which can be checked for reference voltage. Depending on the type of engine, Camshaft Sensor and Crankshaft Sensor should be checked for resistance and proper signal output. Finally, Knock Sensors detect engine knock which should be checked for reference voltage and resistance. If any component fails these checks, replacement may be necessary.
    Posted by GMPartsGiant Specialist
    Q:
    How to check and replace Camshaft Position Sensor,Coolant Temperature Sensor,Crankshaft Position Sensor,Intake Manifold Temperature Sensor,Knock Sensor,Oxygen Sensor,Vehicle Speed Sensor,Neutral Safety Switch,MAP Sensor and Throttle Position Sensor on GMC Sonoma? Posted by Customer
    A:
    Various engine sensors and components have checking procedures,the engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature, and a failure in the circuit can cause trouble codes. The resistance should be measured when cold and warm while ensuring reference voltage from PCM is around 5.0 volts for the verification. Manifold Absolute Pressure (MAP) Sensor monitors changes in intake manifold pressure then varies its voltage output accordingly. Look at the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes. Intake Air Temperature (IAT) Sensor acts as a thermistor where you can measure its resistance at different temperatures to make sure it changes as expected. Also, use a scan tool to monitor the IAT sensor for performance. The oxygen sensor in exhaust detects oxygen content which you can check its millivolt signal while warming up your engine. Check whether the oxygen sensor heater has correct voltage or not. Vehicle Speed Sensor (VSS) provides speed data to PCM which can be checked for reference voltage. Depending on the type of engine, Camshaft Sensor and Crankshaft Sensor should be checked for resistance and proper signal output. Finally, Knock Sensors detect engine knock which should be checked for reference voltage and resistance. If any component fails these checks, replacement may be necessary.
    Posted by GMPartsGiant Specialist
    Q:
    How to check and replace Camshaft Position Sensor,Coolant Temperature Sensor,Crankshaft Position Sensor,Intake Manifold Temperature Sensor,Knock Sensor,Oxygen Sensor,Vehicle Speed Sensor,Neutral Safety Switch,MAP Sensor and Throttle Position Sensor on GMC Jimmy? Posted by Customer
    A:
    Various engine sensors and components have checking procedures,the engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature, and a failure in the circuit can cause trouble codes. The resistance should be measured when cold and warm while ensuring reference voltage from PCM is around 5.0 volts for the verification. Manifold Absolute Pressure (MAP) Sensor monitors changes in intake manifold pressure then varies its voltage output accordingly. Look at the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes. Intake Air Temperature (IAT) Sensor acts as a thermistor where you can measure its resistance at different temperatures to make sure it changes as expected. Also, use a scan tool to monitor the IAT sensor for performance. The oxygen sensor in exhaust detects oxygen content which you can check its millivolt signal while warming up your engine. Check whether the oxygen sensor heater has correct voltage or not. Vehicle Speed Sensor (VSS) provides speed data to PCM which can be checked for reference voltage. Depending on the type of engine, Camshaft Sensor and Crankshaft Sensor should be checked for resistance and proper signal output. Finally, Knock Sensors detect engine knock which should be checked for reference voltage and resistance. If any component fails these checks, replacement may be necessary.
    Posted by GMPartsGiant Specialist
    Q:
    Where are the two CKP sensors located for the 2000 Cadillac DeVille? Posted by Customer
    A:
    They are located on the front of the block, just above and to the left of the oil filter.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Crankshaft Position Sensor
    Q:
    What should be done after performing a check procedure for the 2004 Chevrolet Astro? Posted by Customer
    A:
    Clear the PCM of all trouble codes by removing the PCM-B fuse or disconnecting the cable from the negative terminal of the battery for at least 30 seconds.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Crankshaft Position Sensor
    Q:
    How should the camshaft sensor and crankshaft sensor be checked for the 2004 Chevrolet Blazer? Posted by Customer
    A:
    The camshaft sensor and crankshaft sensor, depending on the engine type, should be checked for resistance and proper signal output.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Crankshaft Position Sensor
    Q:
    What should you do if the Malfunction Indicator Light (MIL) is illuminated after installing the CKP sensor for the 2001 Chevrolet Express? Posted by Customer
    A:
    If the MIL is illuminated after installation, it may indicate a Diagnostic Trouble Code (OTC) related to the CKP system variation not learned. In this case, a dealer technician can perform the necessary procedure to relearn the variation between the CKP and CMP sensors and clear the OTC from the PCM's memory.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Crankshaft Position Sensor
    Q:
    Where is the knock sensor located on the engine for the 2004 Chevrolet Express? Posted by Customer
    A:
    The knock sensor is located on the rear part of the engine block, to the left of the distributor.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Knock Sensor
    Q:
    What does the manifold absolute pressure (MAP) sensor do and how can it be checked for the 2003 GMC Sonoma? Posted by Customer
    A:
    The manifold absolute pressure (MAP) sensor monitors intake manifold pressure changes and varies its voltage output accordingly. To check it, you should check the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Crankshaft Position Sensor
    Q:
    What does the manifold absolute pressure (MAP) sensor do and how can it be checked for the 2001 GMC Jimmy? Posted by Customer
    A:
    The manifold absolute pressure (MAP) sensor monitors intake manifold pressure changes and varies its voltage output accordingly. To check it, you should check the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Crankshaft Position Sensor
    Q:
    What does the oxygen sensor in the exhaust do and how can it be checked for the 2002 Chevrolet S10? Posted by Customer
    A:
    The oxygen sensor in the exhaust monitors oxygen content. To check it, you can check its millivolt signal while the engine warms up. It is also important to inspect the oxygen sensor heater and ensure it receives proper voltage.
    Posted by GMPartsGiant Specialist
    See expert answers on similar Crankshaft Position Sensor
    If you have any questions about this product, please don't hesitate to ask us. We will be happy to help you!

Genuine GM Part 21024981, the Right Choice

To ensure reliability, purchase GM part # 21024981 Sensor Assembly, Knock. It is sometimes referred to as GM Crankshaft Position Sensor, GM Knock Sensor. Directly from GM, genuine parts are superb with regards to quality, longevity, and fit. Every single part passed stringent quality testing, so you can be sure that it's safe, durable, and built to perform like your original parts. This part fits specific Cadillac Deville, Eldorado, Seville models. It fits Chevrolet Blazer, S10, Silverado. It also fits GMC Savana, Sierra, Sonoma. This also fits Saturn SC1, SC2, SW2.

GMPartsGiant.com is a leading supplier of genuine GM parts and accessories such as GM 21024981 Sensor Assembly, Knock. You're certainly in the right place if you're searching for the great cost-effective OEM GM parts. Look no further than our vast inventory of genuine GM parts offered at unbeatable online prices, all of which are backed by the manufacturer's warranty. Not to forget, our hassle-free return policy and quick delivery service ensure a smooth shopping experience for you. For detailed GMC parts information, click here.

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