Knock Sensor for BMW 3 Series — Price, Symptoms & Replacement Guide
Category: Engine | Failure Severity: High | Replacement Cost in India: ₹3,000–₹12,000
What is the Knock Sensor?
The knock sensor detects abnormal combustion (knocking) in the engine.
How the Knock Sensor Works
It sends signals to ECU to adjust ignition timing.
Why the Knock Sensor is Important
Prevents engine damage from knocking.
Common Problems with the Knock Sensor
- Sensor failure
Warning Symptoms of a Failing Knock Sensor
- Engine knocking
- Check engine light
Common Causes of Knock Sensor Failure
- Electrical issues
Impact on Car Performance
Faulty sensor may lead to engine damage.
DIY Fix Guide — Step by Step
- Scan ECU
- Replace faulty sensor
Maintenance Tips
- Regular diagnostics
Knock Sensor Replacement Cost in India
Expect to pay between ₹3,000 and ₹12,000 for genuine parts plus labour at an authorised BMW workshop. Local garages and aftermarket parts can be 20–40% cheaper but may compromise warranty.
Where to Buy Knock Sensor Online
Search trusted Indian car-parts retailers like Boodmo, Amazon India and Flipkart for genuine and OEM-grade Knock Sensor listings.
When to Replace the Knock Sensor
Replace when knocking persists or sensor fails.