Ignitions and Electrical› Charging Systems

Bosch

Knock Sensor

$36.00

SKU: 390-112-004

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Bosch 390-112-004 is a performance sensor. It is designed for use with Mazda MX-5 NA (Mk1) and NB (Mk2) models.
Show original supplier description
The M’z Labo Bosch Knock Sensor Kit is engineered for Mazda MX-5 NA and NB models, providing precise and dependable knock detection, particularly for engines equipped with standalone ECUs or those that have been modified. The kit utilizes genuine Bosch components to produce a consistent, linear signal across a broad frequency spectrum, which is crucial for accurately identifying detonation events under various engine loads and conditions. Accurate knock monitoring is vital for safeguarding your engine, especially when running higher compression ratios, advanced ignition timing, or forced induction setups. By facilitating a rapid ECU response to knock events, this sensor kit significantly minimizes the risk of engine damage, thereby supporting long-term reliability and sustained performance. A Helicoil insert is provided to ensure a secure mounting point where needed, making the kit suitable for both new builds and existing applications. Features include a genuine Bosch knock sensor, a linear signal across a wide frequency range for accurate detection, and support for increased performance and engine longevity. The kit comes with a Bosch limited lifetime warranty. Kit contents include the genuine Bosch knock sensor, a mounting bolt, a Helicoil insert, and an EV1 connector with a pigtail.
Vehicle Symptoms
  • Dimming headlights at idle
  • Battery warning light on dashboard
  • Slow engine crank or no start
  • Electrical accessories failing intermittently
  • Dead battery after short drives
Diagnostic Codes
  • P0562 – Sys V Low
Relevant Conversations
  • battery light on and dim headlights
  • alternator not charging battery
  • Bosch performance alternator upgrade
  • symptoms of a failing alternator
  • high output alternator for my car
  • P0562 code causes and fix
  • alternator replacement cost and labor
  • best alternator for audio system
  • alternator vs battery issue diagnosis
  • Bosch 390-112-004 alternator review

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandBosch
Part Number390-112-004
CategoryIgnitions and Electrical
5,000+ Trusted brands
1M+ Enthusiasts
5M+ Parts sold
(760) 282-4645 hello@motormia.co

Buy with Confidence

Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

View Full Return Policy

Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

View Full Shipping Policy