P0329
Fix within a few daysKnock Sensor 2 Circuit Intermittent (Bank 1 or Single Sensor)
Code P0329 means your engine's knock sensor 2 circuit has an intermittent fault. Common causes: Faulty knock sensor (70%), wiring issues (25%). Drivability: Yes, for short trips only. Repair cost: $30-$150 DIY, $130-$750 professional.
Can I Drive With P0329?
Yes, for short trips only
Essential trips under 10 miles, avoid highways and heavy acceleration
Stop driving immediately if: Flashing CEL, loud engine knocking, significant power loss, or any burning smell.
Symptoms of P0329
- 1Reduced engine power or acceleration
- 2Poor fuel economy
- 3Engine pinging or knocking sounds (often not audible to driver)
- 4Check Engine Light illuminated
Common Causes of P0329
Parts most likely causing this code, ranked by probability
The knock sensor itself has an internal fault, causing an intermittent signal to the engine computer.
70% of P0329 cases are fixed by replacing this part
Damaged, corroded, or loose wiring or a faulty connector to the knock sensor causes an intermittent signal.
25% of P0329 cases are fixed by repairing or replacing wiring/connectors
A rare internal fault within the engine computer can cause it to misinterpret or fail to receive the knock sensor signal.
5% of P0329 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the knock sensor's wiring harness for any cuts, frays, or signs of rodent damage.
- Ensure the electrical connector to the knock sensor is fully seated and free of corrosion.
How to Diagnose P0329
- 1Visually inspect Knock Sensor 2 and its wiring harness for any obvious damage, fraying, or corrosion.
- 2Check the electrical connector at the knock sensor for a tight fit and clean terminals.
- 3Use a multimeter to test the knock sensor's resistance and voltage output according to your vehicle's service manual specifications.
- 4Inspect the engine for any signs of actual knocking or pinging that could be triggering the sensor, such as low octane fuel or carbon buildup.
- 5If all other checks pass, consider consulting a professional for advanced ECM diagnostics.
P0329 on Popular Vehicles
Toyota Camry
2002-2017On V6 engines, knock sensors are often located under the intake manifold, requiring significant labor to replace. This is a common failure point.
70% fixed by replacing the knock sensor
Honda Accord
2003-2017Similar to Toyota V6s, some Honda V6 engines place knock sensors under the intake manifold, increasing repair complexity and cost.
70% fixed by replacing the knock sensor
Ford F-150
2004-2024Location of knock sensors varies significantly by engine (V6 vs. V8) and year. Some are easily accessible on the block, others require intake removal.
65% fixed by replacing the knock sensor, 25% by wiring repair
Frequently Asked Questions
What does P0329 mean?
P0329 indicates that the engine's computer (ECM/PCM) is detecting an intermittent electrical problem with the Knock Sensor 2 circuit. This sensor detects engine knocking or pinging.
Can I drive with P0329?
Yes, for short trips only. Your engine's computer will likely retard timing to prevent damage, which means reduced power and fuel economy. Prolonged driving can lead to engine damage if actual knocking is occurring.
Will P0329 clear itself?
No, P0329 will not clear itself. The intermittent fault needs to be diagnosed and repaired. The Check Engine Light will remain on until the underlying issue is resolved.
How do I fix P0329 myself?
Start by inspecting the knock sensor's wiring and connector for damage. If they look good, test the sensor with a multimeter. If the sensor tests bad or shows an intermittent signal, replace Knock Sensor 2.
How much does it cost to fix P0329?
DIY repair costs range from $30 to $150 for a new knock sensor. Professional repair costs typically range from $130 to $750, depending on the sensor's location and labor involved.
P0329 keeps coming back - why?
P0329 often returns if the wiring harness or connector was not thoroughly checked, if the replacement sensor is faulty, or if there's an underlying engine issue causing actual knocking that the sensor is correctly reporting.
Will P0329 fail emissions/smog test?
Yes, P0329 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most jurisdictions.
What's the difference between P0329 and P0325?
P0325 indicates a general fault in the Knock Sensor 1 circuit, while P0329 specifically points to an *intermittent* fault in the Knock Sensor 2 circuit. P0329 implies the signal is sometimes present and sometimes not.
P0329 on Toyota Camry?
On many Toyota Camry V6 engines, the knock sensors are located under the intake manifold, making replacement a labor-intensive job. This significantly increases the repair cost due to the extra labor required to access the sensor.
Questions to Ask Your Mechanic
Did you check the wiring harness and connector for corrosion or damage before condemning the sensor?
Good answer: Yes, I performed a visual inspection and continuity test on the wiring from the sensor to the ECM. The connections are clean and secure.
What were the resistance and voltage readings from the knock sensor?
Good answer: The sensor showed intermittent open circuit or out-of-spec resistance readings, indicating an internal fault. Voltage output was inconsistent.
Repair Cost Estimate
DIY Repair
Parts only
$30-$150
Shop Repair
Parts + labor
$130-$750
Save $100-$600 by doing it yourself
Difficulty
intermediate
Time
1-4 hours
Intermediate - Requires basic diagnostic tools like a multimeter and potentially involves removing the intake manifold, which can be complex for beginners.
Cost of Waiting
Ignoring P0329 can lead to your engine running with retarded timing, resulting in reduced power and poor fuel economy. More critically, if the sensor is failing to detect actual engine knocking, it can lead to severe internal engine damage over time, turning a $150 sensor replacement into a multi-thousand dollar engine rebuild.
While You're In There...
If the knock sensor is located under the intake manifold, these gaskets must be replaced whenever the manifold is removed to prevent vacuum leaks.
Often accessible when the intake manifold is removed, replacing the PCV valve is a low-cost maintenance item that prevents oil sludge buildup and maintains engine health.
Tools You'll Need
- Basic hand tools (sockets, wrenches)
- Multimeter
- Torque wrench (if intake manifold removed)
- Pliers
- Wire brush (for cleaning connections)
P0329 is a common sensor code. While it can be tricky to access on some engines, the repair is straightforward once the sensor is located, and your engine will regain full performance afterward.
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Your Next Steps
Step 1: Perform a thorough visual inspection of the knock sensor and its wiring. Look for any obvious damage, loose connections, or corrosion.
Step 2: If the visual inspection doesn't reveal the issue, use a multimeter to test the knock sensor's resistance and voltage output. Compare readings to your vehicle's service manual specifications.
Step 3: If the sensor tests faulty or shows intermittent readings, you'll likely need to replace Knock Sensor 2. Be prepared for potential intake manifold removal on some vehicles.