AutoCodes – Mercedes-Benz – P0329 Mercedes-Benz

P0329 Mercedes-Benz Code - Knock Sensor Circuit Intermittent

Quick Answer

The knock sensor is attached to the cylinder block. Common causes include Faulty Knock Sensor, Knock Sensor circuit poor electrical connection, Knock Sensor harness is open or shorted. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0329 Mercedes-Benz indicates Knock Sensor Circuit Intermittent.
Common causes: Common causes include Faulty Knock Sensor, Knock Sensor circuit poor electrical connection, Knock Sensor harness is open or shorted.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 2,782

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 16, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0329 Mercedes-Benz Description

The knock sensor is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is sensed as vibrational pressure. This pressure is converted into a voltage signal and sent to the Engine Control Module (ECM).

OBDII Code P0329 Mercedes-Benz - Knock Sensor Circuit Intermittent - AutoCodes.com — P0329 Mercedes-Benz Code - Knock Sensor Circuit Intermittent

What does this mean?

What are the Possible Causes of the DTC P0329 Mercedes-Benz?

Faulty Knock Sensor
Knock Sensor circuit poor electrical connection
Knock Sensor harness is open or shorted
Faulty Engine Control Module (ECM)

How to Fix the DTC P0329 Mercedes-Benz?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P0329 code means that the Knock Sensor is not working properly. Problems with the knock sensor will not cause an engine performance problems. Replacing the knock sensor usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0329 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0329 Mercedes-Benz code?

Need more information on how to fix the P0329 Mercedes-Benz code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0329 Mercedes-Benz code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0329 Mercedes-Benz Code

1. What does the OBDII code P0329 mean for a Mercedes-Benz?

P0329 indicates an intermittent issue in the knock sensor circuit, meaning the sensor is not consistently detecting engine knocking or is sending erratic signals to the ECU.

2. What are the common symptoms of the P0329 code?

Symptoms may include reduced engine performance, poor fuel economy, illuminated check engine light, engine knocking or pinging, and potential hesitation during acceleration.

3. What causes the P0329 code on a Mercedes-Benz?

Common causes include a faulty knock sensor, damaged or corroded wiring or connectors, an ECM issue, or engine-related problems like excessive carbon buildup or incorrect ignition timing.

4. Can I drive my Mercedes-Benz with a P0329 code?

While the car may still be drivable, ignoring the code can lead to engine damage due to uncontrolled knocking or misfires. Itâ€™s best to address the issue promptly.

5. How do I diagnose the P0329 code?

Diagnosis typically involves scanning for stored codes, inspecting the knock sensor and its wiring, testing sensor resistance, and checking for engine-related issues like carbon buildup.

6. How do you fix the P0329 code on a Mercedes-Benz?

Repairs may include replacing the knock sensor, repairing or replacing damaged wiring or connectors, cleaning carbon buildup, or reprogramming the ECM if needed.

7. How much does it cost to fix a P0329 code on a Mercedes-Benz?

The cost varies depending on the issue. Replacing a knock sensor may cost $150-$400, while wiring repairs or ECM programming could add to the expense.

8. Can a bad knock sensor cause engine damage?

Yes, a faulty knock sensor may fail to detect engine knocking, which can lead to severe damage over time if the issue is not addressed.

9. What tools are needed to troubleshoot a P0329 code?

Basic tools include an OBDII scanner, a multimeter for testing the sensor, and possibly a wiring diagram to inspect the circuit.

10. How can I prevent the P0329 code from recurring?

Regular maintenance, such as cleaning carbon deposits, using high-quality fuel, and ensuring proper engine tuning, can help prevent knock sensor issues.