P0330 Code: Knock Sensor 2 Circuit Malfunction (Bank 2)
The second knock sensor, usually the one for the bank without cylinder 1, has a circuit fault.
At a glance
Severity: Low
- Meaning
- Knock Sensor 2 Circuit Malfunction (Bank 2)
- System
- Ignition & Misfire · Powertrain
- Safe to drive?
- Yes, short term
- Typical repair cost
- $80–$1,100
- DIY difficulty
- Moderate
P0330 is the bank 2 counterpart of P0325: the engine computer isn't getting a usable signal from knock sensor 2. On a V6 or V8, that's the sensor for the bank that doesn't contain cylinder 1, which is the passenger side on GM V8s and the driver's side on Ford V8s. Some inline engines also have two knock sensors, each listening to a group of cylinders; there, P0330 simply means the second sensor, typically covering the rear cylinders. The useful thing about this code is that you usually have a working sensor 1 on the same engine to compare against. If P0325 is also set, both circuits failed together, and the cause is almost always something they share, such as a sub-harness, a connector or a ground, rather than two sensors dying at once.
Can I keep driving? Fine for normal driving. The computer retards timing on that bank, or on the whole engine, so expect a little less power. Use the recommended octane and avoid heavy towing until it's repaired.
How to read P0330
- P Powertrain
- 0 Generic (SAE)
- 3 Ignition / misfire
- 30 Specific fault
Symptoms
- Check-engine light on, sometimes with P0325 as well
- Slightly flat acceleration and lower fuel economy
- Pinging under load that the computer no longer controls
- Code appeared after work at the back of the engine or under the intake
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Damaged harness to sensor 2, often a longer run across the back of the engine near hot exhaust or EGR parts
- Failed knock sensor 2
- Shared sub-harness, connector or ground failing, especially when P0325 is also set
- Sensor 2 loose or torqued incorrectly
- Connector disturbed or not fully latched during earlier repairs
- Engine computer knock input fault
Diagnosis step by step
Confirm which sensor is number 2
Check a diagram for your engine. On V engines it's the sensor on the bank without cylinder 1. On inline engines with two sensors it usually listens to the rear cylinders. Knowing this saves pulling the wrong side of the engine apart.
Tools: Flashlight
Use sensor 1 as a reference
At the engine computer connector, measure the resistance of both knock sensor circuits, battery disconnected. Sensor 1's circuit gives you the value a good circuit should read on this engine. If sensor 2 reads open or very different, the fault is somewhere between that connector and sensor 2.
Tools: Multimeter
Split harness and sensor
Unplug sensor 2 and measure the sensor alone, then the harness alone for continuity and shorts to ground. This tells you whether to buy a sensor or repair wires, which matters when the sensor is under the intake.
Tools: Multimeter
If P0325 is also set, check shared parts first
Two knock codes at once point to the part both circuits share: a Y-shaped sub-harness, a common connector, a shield ground or the computer's knock input. Inspect those before replacing both sensors.
Tools: Flashlight, Multimeter
Tap test after repair
With the engine idling and a scan tool showing knock activity or retard, lightly tap the block near sensor 2. The reading should react. Then clear the code and road-test with some moderate acceleration.
Tools: OBD-II scanner
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Repair or replace sensor 2 harness | No | $120–$450 |
| Replace knock sensor 2 (accessible) | Yes | $150–$400 |
| Replace both sensors and sub-harness under the intake | No | $500–$1,100 |
| Repair shared ground or connector | No | $80–$250 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
BMW
BMW inline-six engines use two knock sensors on the intake side of the block, one for cylinders 1 to 3 and one for cylinders 4 to 6. They sit under the intake manifold, so a sensor 2 fault means removing the intake. Replace the intake gaskets at the same time.
Chevrolet
On GM V8s, bank 2 is the passenger side with the even-numbered cylinders. Make sure you're working on the correct side before removing parts, because Ford numbers the banks the other way around.
Emissions / smog test impact
Will fail
A P0330 with the check-engine light on fails an OBD emissions test even though the car usually runs normally. After repair, drive until the monitors report ready before retesting.
Frequently asked questions
Is bank 2 the driver or passenger side?
It depends on the manufacturer. Bank 1 is always the side with cylinder 1. On GM and Chrysler V8s, bank 2 is the passenger side; on Ford V8s, it's the driver's side. On transverse V6s, check a diagram for your engine.
I have P0325 and P0330 together. Are both sensors bad?
Possibly, but more often it's something they share: a common harness, connector or ground, or damage from a single event like a coolant leak under the intake. Diagnose the shared parts first.
My car is an inline-four. Why does it have a bank 2 knock code?
Some inline engines have two knock sensors, each covering part of the engine. The generic code naming calls the second one bank 2 even though there's only one cylinder bank.
Can I swap the sensors to test them?
Not easily, since each is bolted to its own spot on the block. It's simpler to compare readings: measure both sensors and both circuits and use the good side as your reference.
Sources
- SAE J2012 – Diagnostic Trouble Code Definitions
- ISO 15031-6 – Road vehicles, diagnostic trouble code definitions (EOBD)
- Manufacturer public service information (cross-checked)
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