P0329
Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor)P0329 is a generic OBD-II powertrain diagnostic trouble code: Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor). It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0329 means
P0329 indicates the Engine Control Module (ECM) has detected an intermittent signal fault in the Knock Sensor 1 circuit on Bank 1 (or the single sensor on an inline engine). The knock sensor is a piezoelectric device bolted directly to the engine block that generates a small voltage signal proportional to engine vibration. The ECM uses this signal to detect abnormal combustion (knock or detonation) and retard ignition timing as a protective response.
Unlike the hard faults of P0327 (low) and P0328 (high), P0329 captures a signal that drops in and out unpredictably — the circuit passes and fails intermittently. Common causes are loose or corroded connector pins, chafed wiring that shorts momentarily under vibration, or a sensor with a cracked piezo element. Because the ECM cannot rely on intermittent feedback, it defaults to conservative timing retard on Bank 1, resulting in a mild but noticeable loss of power and fuel economy. Although symptoms may seem minor, the code should be diagnosed promptly: uncorrected ignition knock can cause piston and bearing damage over time.
Common causes
Most-frequently reported root causes when P0329 is logged.
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1
Corroded, loose, or damaged knock sensor 1 connector pins causing intermittent contact
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2
Chafed or pinched signal wire that shorts or opens under engine vibration
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3
Faulty knock sensor 1 with cracked or degraded piezoelectric element
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4
Knock sensor mounting bolt loose, reducing sensor-to-block coupling
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5
Moisture or oil intrusion into the sensor connector causing resistance spikes
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6
Ignition misfires generating abnormal vibration that confuses the sensor signal
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7
Internally faulty PCM/ECM knock-input circuit (rare, diagnose last)
Symptoms drivers notice
How to diagnose P0329
A typical diagnostic flow when this code is present.
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1
Retrieve all stored DTCs and note freeze-frame data; check for related misfire or fuel trim codes that could indicate a root cause
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2
Perform a thorough visual inspection of the knock sensor 1 wiring harness and connector — look for chafing, melted insulation, corrosion on pins, and loose connector latches
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3
With ignition on, verify 5 V reference is present at the sensor connector; check for a clean chassis ground on the sensor return wire
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4
Use a DVOM to measure knock sensor resistance across its terminals and compare to manufacturer specification (typically 4–8 MΩ for flat-response sensors); replace sensor if out of range
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5
With the engine running, lightly tap the engine block near the sensor with a metal tool while monitoring knock sensor voltage on a scan tool — a healthy sensor will cause the ECM to briefly retard timing
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6
Wiggle the harness and connector while monitoring live knock sensor data for signal dropouts; this isolates intermittent wiring faults
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7
If wiring and sensor test good, check for relevant Technical Service Bulletins (TSBs) before considering PCM replacement
Related powertrain codes
Frequently asked questions
Can I drive with a P0329 code?
Short-term driving is possible, but the ECM will apply a default timing retard on Bank 1 as a protective measure, reducing power and fuel efficiency. More importantly, if the sensor fails completely during driving, actual engine knock may go undetected, risking piston or bearing damage. Diagnose and repair promptly.
Is P0329 the same as P0327 or P0328?
They all relate to Knock Sensor 1 on Bank 1, but indicate different fault types. P0327 is a stuck-low (open circuit or failed sensor), P0328 is stuck-high (short to voltage), and P0329 is intermittent — the signal is erratic, passing and failing unpredictably. P0329 can be harder to diagnose because the fault may not be present during bench testing.
Where is Knock Sensor 1 located?
It is typically threaded into the engine block on Bank 1 (the side containing cylinder #1), often underneath the intake manifold. On inline 4- and 6-cylinder engines there is usually a single sensor. Access can require intake manifold removal on some vehicles.
Will replacing the knock sensor always fix P0329?
Not always. Because P0329 is an intermittent code, the fault is often in the wiring harness or connector rather than the sensor itself. Always inspect and test the circuit thoroughly before replacing the sensor, as a wiring repair may be all that is needed.
Disabling P0329 in software
RaceTune can permanently disable P0329 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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