BMW/MINI 13627598861 KNOCK SENSOR
Product Specifications
Product quality
OEM Equivalent Grade
10 sold
Wholesale price USD
$2.57
Wholesale price CNY
¥17.4
bolt MOQ (Minimal order)
10 pcs
local_shipping Production time
34 days
package_2 Shipping Weight:
0.046 kg
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Application (cross references) 1
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| BMW/MINI | 13627598861 |
Overview & Operating Principle
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The KNOCK SENSOR is a piezoelectric vibration sensor bolted directly to the engine block or cylinder head that detects the characteristic high-frequency structural vibration signature of combustion knock — the uncontrolled auto-ignition of the end-gas charge ahead of the propagating flame front — and transmits this signal to the ECU, which uses it to retard ignition timing on the affected cylinder until the knock event ceases, then advances timing back toward the optimum point in a continuous closed-loop process that maximises thermal efficiency while protecting the engine from the mechanical damage that sustained knock produces. The sensor element is a piezoelectric ceramic disc that generates a voltage output proportional to the mechanical stress applied to it; when knock occurs, the pressure wave from the uncontrolled combustion event propagates through the engine structure as a high-frequency vibration at 5–15 kHz — the characteristic knock frequency band — that stresses the piezoelectric element and produces a distinctive voltage burst that the ECU's knock detection circuit filters from background engine vibration using a bandpass filter tuned to the knock frequency range for the specific engine. The ECU monitors knock on a cylinder-individual basis by correlating the sensor signal's timing with each cylinder's power stroke, allowing it to retard timing selectively on only the knocking cylinder rather than applying a global timing retard that would penalise all cylinders for knock in one.
This unit — BMW/MINI 13627598861 — is manufactured to OEM-equivalent specifications: piezoelectric element sensitivity and resonant frequency, sensor body dimensions and mounting bolt hole diameter, output signal connector pinout, shielded cable length where applicable, and operating temperature range are matched to the original part. Supplied as a direct replacement for standard fitment. Available wholesale from 2.57 USD, MOQ 10 pcs, production lead time 34 days.
Knock sensors fail through piezoelectric element cracking from overtightening the mounting bolt — the ceramic element is mechanically pre-stressed by the correct mounting torque to optimise its sensitivity; overtightening crushes the element beyond its design limit and fractures it, producing either no output or an abnormally high constant output; through connector pin corrosion from underbonnet moisture that increases signal circuit resistance and reduces the sensor's effective output voltage; and through element sensitivity drift from sustained thermal cycling at engine block temperatures above the sensor's rated limit. A failed knock sensor causes the ECU to apply a fixed maximum ignition timing retard as a protective measure — the engine will not knock but runs with measurably reduced power and increased fuel consumption while the fault persists.
Symptoms & Diagnostics
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Check Engine light with knock sensor circuit fault codes P0325–P0334 — sensor circuit open, short, or signal out of range — the most common presentation of knock sensor failure; the ECU has detected that the sensor signal is absent, fixed, or outside the expected voltage window; confirm by reading the sensor output voltage on scan tool live data with the engine running — a serviceable sensor shows a low-level alternating signal that increases in amplitude when knock is induced by briefly loading the engine on low-octane fuel.
Reduced power output and increased fuel consumption without misfire codes — the engine runs smoothly but feels less responsive than normal — the ECU has applied a fixed ignition timing retard in response to a knock sensor fault code; the timing retard is a protective default that prevents engine damage but significantly reduces thermal efficiency; the power and fuel economy penalty is proportional to the degree of timing retard applied and is immediately noticeable on a vehicle that previously performed correctly.
Engine knock or pinging noise audible under load — particularly under hard acceleration or when climbing a gradient in a high gear — a knock sensor fault has caused the ECU to disable the knock control loop; without knock feedback, the ECU cannot detect and retard timing when knock occurs; the engine knocks at the base timing map setting which may be optimistic for the fuel octane available; sustained audible knock on an engine without active knock control causes rapid piston crown erosion and connecting rod bearing damage.
Knock sensor fault code that returns immediately after sensor replacement — the mounting bolt was overtightened, fracturing the new sensor's piezoelectric element; or the wiring harness has a break or short between the sensor and the ECU that was not identified before the new sensor was installed; verify the mounting torque against the OEM specification and perform a wiring continuity test before condemning a second sensor.
Scan tool live data showing knock sensor signal permanently at zero volts or permanently at a fixed elevated voltage regardless of engine operating conditions — a zero-voltage signal indicates the sensor output circuit is open — broken sensor element, broken wire, or corroded connector; a fixed elevated voltage indicates the signal wire is shorted to a voltage source; both conditions produce the same fault code but require different repairs — continuity testing identifies the specific fault.
Knock sensor fault code that appears only at elevated engine temperatures and clears when the engine cools — thermal expansion of the engine block is changing the contact force on the sensor mounting bolt, altering the piezoelectric pre-stress and shifting the sensor's sensitivity out of the ECU's expected range; this temperature-correlated pattern indicates either an incorrect mounting torque applied previously or a sensor whose element has drifted from thermal fatigue.
Logistics & Customs
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International HS Code
8543.70
EAEU Customs Code (TN VED)
8543 70 900 9
Typical Net Weight
0.046 kg
Country of Manufacture
China
Standard MOQ
10 pcs
Production Lead Time
34 days
Always verify the exact 8-digit or 10-digit subheading with your customs broker for the destination country, as tariff schedules and duty rates vary by jurisdiction.
Installation Tips
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- Test the wiring harness for continuity and insulation resistance between the sensor connector and the ECU connector before fitting the new sensor — a break in the shielded signal cable or a short to ground in the harness will produce the same knock sensor fault code on the new sensor as on the original; use a multimeter to confirm signal wire continuity and confirm no short between signal wire and shield or ground before installing the replacement; replacing a serviceable sensor into a faulty harness wastes cost and does not resolve the fault code.
- Clean the sensor mounting boss on the engine block meticulously — remove all rust, debris, and old thread lock compound from the boss face and mounting thread with a wire brush and brake cleaner; any debris under the sensor body prevents uniform contact between the sensor base and the block surface, altering the mechanical coupling between the block and the piezoelectric element and reducing the sensor's ability to detect knock vibration accurately.
- Torque the mounting bolt to the OEM specification using a torque wrench — this is the single most critical step in knock sensor installation — the piezoelectric element's sensitivity is calibrated for the design mechanical pre-stress imposed by the correct mounting torque, typically 15–25 Nm depending on the engine; undertightening produces insufficient pre-stress and reduces sensitivity; overtightening by even 30% above specification crushes and fractures the ceramic element, destroying the new sensor before the engine is started; always use a torque wrench — never tighten by feel.
- Do not apply thread lock compound to the mounting bolt unless specifically required by the OEM — thread lock changes the friction coefficient of the thread, altering the relationship between torque wrench reading and actual bolt clamping force; on knock sensor mounting bolts where the clamping force directly determines the sensor's sensitivity, a thread lock application without a corresponding torque correction produces an incorrectly pre-stressed element even when the correct torque value is applied.
- Route the sensor cable away from ignition HT leads, ignition coils, and the alternator output wire — the knock sensor signal is a low-amplitude millivolt-level output that is extremely sensitive to electromagnetic interference from these sources; a cable routed in contact with an HT lead or coil primary wire picks up ignition interference that the ECU interprets as knock events, causing the ECU to retard timing unnecessarily on every ignition cycle; use the original cable routing clips and maintain the OEM separation distance from interference sources.
- Install the new KNOCK SENSOR (BMW/MINI 13627598861), reconnect the shielded cable connector until it clicks, clear all knock sensor fault codes with an OBD-II scanner, start the engine and run to operating temperature, confirm the fault code does not return, and verify on scan tool live data that the knock sensor signal shows a low-level alternating output that responds to engine load changes before returning the vehicle to service.
Tools: torque wrench (calibrated 15–25 Nm range — mandatory), multimeter for harness continuity test, wire brush and brake cleaner for boss cleaning, OBD-II scanner with live knock sensor signal data, cable routing clips matching original positions.
Frequently Asked Questions
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Why is the mounting bolt torque so critical for knock sensor performance compared to other sensors?
Unlike other engine sensors that measure a fluid property or a position, the knock sensor measures structural vibration transmitted through solid contact between the sensor body and the engine block. The piezoelectric element inside the sensor generates voltage in proportion to the mechanical stress applied to it — this stress is the combination of the pre-stress from the mounting bolt and the dynamic stress from knock vibration. The mounting bolt's clamping force sets the operating point on the piezoelectric element's sensitivity curve; the OEM torque value places this operating point at the designed sensitivity. Undertightening places the element at a lower pre-stress where its sensitivity is insufficient to detect low-amplitude knock; overtightening places it beyond its elastic limit where the ceramic fractures. This is why hand-feel tightening — which can produce anywhere from 10 to 40 Nm depending on the technician — is never acceptable for knock sensor installation. ok.parts supplies knock sensors at wholesale MOQ from 2.57 USD per unit.
Can the ECU's knock control be verified as functioning correctly after sensor replacement without inducing actual knock?
Knock sensor function can be verified without inducing engine knock by two methods: first, with the engine running at idle, tap the engine block near the sensor mounting location with a metal rod or small hammer — a functional sensor and ECU knock detection circuit will show a brief ignition timing retard on the scan tool live data in response to the impact vibration; second, monitor the knock sensor raw voltage signal on scan tool live data during a moderate acceleration — a functional sensor shows increasing signal amplitude as engine load and base vibration increase, returning to low amplitude at light throttle. If both methods show the expected response and no fault codes are stored after clearing, the knock control system is confirmed functional without requiring fuel with reduced octane to induce actual detonation events.
How does the OEM-equivalent aftermarket unit compare to the genuine OEM part?
OEM-equivalent units in this catalogue replicate the current OEM design geometry and material specification. Quality is verified against OEM cross-reference data. When ordering in bulk, confirm with our team that the specification matches the latest OEM revision for your application.
Is white-label or custom packaging available for wholesale orders?
Yes. ok.parts works directly with the manufacturing facility and can accommodate neutral white-label packaging or fully branded packaging with your company logo, part numbers, and barcode. Minimum order quantities and lead times for custom packaging may differ from standard stock. Contact the team via the inquiry form to discuss your specific requirements.
Frequently Replaced Together
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| Part | Reason for Combined Replacement |
|---|---|
| Knock Sensor Wiring Harness Shielded signal cable — application-specific | The knock sensor signal cable carries a millivolt-level output that is uniquely vulnerable to electromagnetic interference from adjacent ignition components. The shielded cable's outer braid provides the electromagnetic isolation that keeps the signal clean — a cable with a damaged shield or a break in the shielding continuity allows ignition interference to contaminate the signal and produce phantom knock events that cause the ECU to retard timing unnecessarily. If the existing cable shows heat damage, chafing, or a damaged connector boot, replace it simultaneously with the sensor to provide the new sensor with an interference-free signal path. |
| Spark Plugs OEM specification — complete engine set | A failed knock sensor that has been applying maximum timing retard as a protective default has also been preventing the engine from knocking — the retarded timing reduced thermal efficiency but protected the engine. If the engine has been operating with a fault code on a knock sensor for a significant mileage, inspect the spark plugs for signs of pre-ignition damage — a white or blistered insulator tip indicates the timing retard was insufficient to prevent all abnormal combustion events. Replace plugs showing thermal damage simultaneously with the sensor to restore the complete ignition system to a known serviceable condition. |
| Ignition Coils COP coil set — application-specific | On engines where the knock sensor fault has been present for an extended period, the ECU's timing retard has increased ignition coil primary current demand as the coils charge to a higher voltage against the retarded combustion cycle. Coils that have been operating under this elevated demand show accelerated insulation fatigue. If the vehicle has accumulated significant mileage with an active knock sensor fault code, inspect the coils for carbon tracking and resistance drift simultaneously with the sensor replacement. |