OBD-II trouble code
P0332: Knock Sensor 2 Circuit Low Input (Bank 2)
The second knock sensor — the one on bank 2 — is reporting signal voltage below the PCM's minimum threshold. If you've already read about P0327, this is the same failure on the opposite cylinder bank: the PCM has effectively gone deaf on that side and falls back to a conservative timing map.
Quick facts
- System
- Powertrain
- Category
- Knock & Other
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $150 – $800
- DIY difficulty
- Intermediate DIY
What does P0332 mean?
P0332 is the bank-2, low-input member of the knock sensor family, and the first thing to sort out is which physical sensor it points to. A knock sensor is a piezo accelerometer bolted to the engine block that listens for detonation — combustion firing too early — so the PCM can retard timing to protect the engine. On a V6 or V8 with two knock sensors, 'sensor 2' lives on bank 2, which is whichever cylinder head does NOT contain cylinder number 1. That side varies by engine family: on most GM LS V8s bank 2 is the passenger side, on many Ford modular V8s it's also the passenger side, but on transverse front-wheel-drive V6s the banks are front and rear rather than left and right. Confirm cylinder 1's location for your specific engine before you start chasing wires, because guessing the wrong bank is the most common way this job goes sideways.
The 'low input' part means the signal voltage on the bank-2 knock sensor circuit has dropped below the minimum the PCM expects — the direct mirror of P0327 on bank 1. It usually means the sensor has failed internally, the wiring has shorted, or the connector has corroded. Knock sensors are a known wear item: the piezo crystal degrades with years of heat and vibration, and most engines past 100,000 miles are candidates.
By far the most notorious platform for this code is the 1999-2007 GM LS-family truck and SUV engines — the 4.8L, 5.3L, and 6.0L found in Silverado, Sierra, Tahoe, Yukon, Suburban, and Avalanche. On these the knock sensors sit in wells underneath the intake manifold, where water from the cowl and engine-bay washing pools and corrodes the sensors and connectors over time. Because bank 2's sensor sits in the same valley as bank 1's, anyone replacing one almost always replaces both — the intake has to come off either way, and the second sensor is usually just as corroded.
Driveability symptoms are subtle because knock sensing is a protection layer, not a load-bearing system. The engine still runs, but it loses the smart ignition advance it would normally make, so you get a slight drop in power and fuel economy. The real long-term risk is that genuine detonation on bank 2 now goes undetected, which under heavy load or low-octane fuel can damage pistons or bearings.
Common causes
- Failed bank-2 knock sensor — piezo element degraded internally (dominant cause on aged engines)
- Corroded bank-2 knock sensor on GM LS trucks where the sensor sits in a moisture-prone well under the intake manifold
- Signal wire shorted to ground on the bank-2 circuit
- Corroded or damaged bank-2 knock sensor connector
- Loose knock sensor — proper torque matters because the sensor relies on mechanical coupling to the block
- Aftermarket knock sensor of incorrect specification
- Wiring chafe along the valley or block on the bank-2 harness run
- PCM signal-input fault (rare)
Symptoms
- Check engine light on with P0332 stored
- Mild loss of power, especially under acceleration
- Reduced fuel economy
- Slightly delayed throttle response
- Possible audible pinging under heavy load if real detonation goes undetected on bank 2
- Engine sounds and runs normally in most cases
Diagnostic steps
- 1.Confirm which physical bank is bank 2 on your engine — it's the head that does NOT contain cylinder 1. Don't assume left or right; verify against the firing-order diagram for your specific engine.
- 2.Pull all codes. P0332 alone is the classic bank-2 sensor failure. P0332 alongside P0333 or the bank-1 codes (P0327/P0328) can point at shared wiring or a PCM-side issue.
- 3.On GM LS trucks, plan for the intake manifold to come off — check for water pooled in the sensor wells before condemning the sensor.
- 4.Disconnect the bank-2 knock sensor connector and measure resistance across the terminals. Most knock sensors read in the hundreds of thousands of ohms to several megohms; an open or near-zero reading confirms a failed sensor.
- 5.If resistance is in spec, back-probe the signal wire at the PCM connector to check harness continuity and look for a short to ground.
- 6.Inspect the connector for green corrosion, oil contamination, or pushed-back pins.
- 7.When replacing, torque the sensor to spec — too loose and it can't read block vibration, too tight and the piezo crystal can crack. On V-engines, replace both knock sensors together since the labor is shared.
- 8.Clear the code, drive through a heavy-load condition such as a highway on-ramp, and confirm it stays off.
Repair cost
$150 – $800
The bank-2 knock sensor part is $30-150 depending on platform. Where the sensor is accessible (many Subaru, Nissan VQ, some Honda V6 engines), total replacement is $150-300. On GM LS trucks where the sensors sit under the intake manifold, expect $500-800 because the intake has to be removed — and most owners replace both sensors at once since labor dominates and the bank-1 sensor is usually just as corroded. Wiring repair runs $100-400 depending on access.
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Related repairs
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.