P0332
Knock Sensor 2 Circuit Low Input (Bank 2)P0332 is a generic OBD-II powertrain diagnostic trouble code: Knock Sensor 2 Circuit Low Input (Bank 2). 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 P0332 means
P0332 indicates that the ECM has measured an abnormally low voltage on the Knock Sensor 2 signal circuit for Bank 2 — typically a reading below approximately 0.5 V when a higher voltage is expected. The knock sensor is a passive piezoelectric device: it generates no output of its own under static conditions, but during normal engine operation it produces a small oscillating voltage proportional to block vibration. A sustained low voltage reading therefore points to an electrical fault rather than a sensor rationality issue.
Most commonly, P0332 results from an open circuit — a broken wire, corroded connector pin, or a sensor whose internal element has failed open. It can also be caused by a short to ground in the signal wire. Because the ECM loses its knock feedback from Bank 2, it applies a fixed timing retard as a protective measure, reducing power and fuel economy on that bank. The fault must be distinguished from P0331 (rationality) and P0334 (intermittent) through circuit testing with a DVOM.
Common causes
Most-frequently reported root causes when P0332 is logged.
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1
Open circuit in the knock sensor 2 signal wire (broken wire or pin-out at connector)
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2
Corroded or damaged knock sensor 2 connector causing high resistance
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3
Knock sensor 2 internal element failed open
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4
Signal wire shorted to ground, clamping the voltage low
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5
Missing or inadequate 5 V reference supply from ECM
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6
Faulty PCM/ECM knock-sensor input circuit (rare)
Symptoms drivers notice
How to diagnose P0332
A typical diagnostic flow when this code is present.
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1
Connect a scan tool and check live Knock Sensor 2 voltage data; a reading near 0 V with the engine running confirms the low-input condition
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2
Inspect the KS2 connector and harness for bent pins, green corrosion, broken wires, or oil contamination
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3
With ignition on, measure voltage at the sensor connector signal pin — should be approximately 5 V reference from the ECM
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4
Measure resistance of the signal wire from the sensor connector back to the ECM connector; an open circuit or reading above a few ohms indicates a wiring fault
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5
Measure knock sensor 2 resistance across its terminals with the sensor disconnected; compare to manufacturer spec (typically 4–8 MΩ for flat-response types) and replace if failed open
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6
Check for a short to ground on the signal wire using a DVOM in resistance mode with all connectors disconnected
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7
If wiring and sensor are within spec, suspect the ECM input circuit and consult TSBs before replacement
Related powertrain codes
Frequently asked questions
Can a bad ground cause P0332?
Yes. A short to chassis ground on the KS2 signal wire will pull the voltage down to near 0 V, mimicking a failed sensor. Always check for unintended ground connections along the harness route before condemning the sensor itself.
How do I test the knock sensor 2 on the bench?
Disconnect the sensor and measure resistance across its terminals with a DVOM. A healthy flat-response piezo sensor typically reads 4–8 MΩ. A reading of zero (short) or infinite (open) indicates a failed sensor. You can also tap the sensor body lightly and observe whether it generates a small AC voltage on an oscilloscope.
Is P0332 always the sensor's fault?
No — in many cases the connector or wiring is at fault. Knock sensors are mounted low on the engine block and are frequently disturbed during nearby repairs (starter, oil pan, engine mounts). Always inspect the harness routing and connector before replacing the sensor.
Will the engine be damaged while P0332 is active?
The ECM applies a conservative default timing retard when knock sensor feedback is lost, so the engine is partially protected. However, the protection is not adaptive — if severe knock occurs the ECM cannot respond in real time, increasing the risk of detonation damage. Repair promptly.
Disabling P0332 in software
RaceTune can permanently disable P0332 — 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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