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P0332 Code: Knock Sensor 2 Circuit Low Input

P0332 Knock Sensor 2 circuit low-input diagnostic illustration

The P0332 OBD-II trouble code means the Powertrain Control Module has detected a Knock Sensor 2 signal voltage that remains below its calibrated threshold.

The generic definition for P0332 is:

Knock Sensor 2 Circuit Low Input — Bank 2

Depending on the vehicle, Sensor 2 may monitor Bank 2, the rear portion of an inline engine or another manufacturer-designated cylinder group.

P0332 does not automatically mean the engine is physically knocking. It means the electrical signal reaching the PCM is too weak.

Common causes include:

A new knock sensor may fix the code, but only if the sensor is actually responsible. Wiring does not become innocent merely because replacing it is less convenient.

P0332 Quick Facts

ItemInformation
Trouble codeP0332
Generic definitionKnock Sensor 2 Circuit Low Input
Sensor locationBank 2 or manufacturer-designated Sensor 2
SystemKnock detection and ignition timing
Fault typeSignal voltage below threshold
SeverityModerate
Safe to drive?Usually short-term if no knocking or overheating is present
Common symptomsCheck Engine Light, reduced power and sluggish acceleration
Common causesFailed sensor, short to ground, resistance or corrosion
Related codesP0330, P0331, P0333 and P0334

What Does the P0332 Code Mean?

P0332 means the voltage or signal amplitude from Knock Sensor 2 remains lower than the PCM expects.

The PCM uses knock-sensor information to detect detonation and temporarily retard ignition timing. If Sensor 2 produces an abnormally weak signal, the PCM may not be able to monitor the affected bank or cylinder group accurately.

The problem may originate from:

The PCM may compensate by using conservative ignition timing or limiting engine performance.

What Does “Circuit Low Input” Mean?

“Circuit low input” means the PCM sees voltage below the calibrated minimum for a specified period.

This can happen when:

P0332 differs from a performance code because the main concern is the low electrical signal rather than whether the signal logically matches engine operation.

What Is Knock Sensor 2?

Knock Sensor 2 is part of the engine’s detonation-monitoring system.

On many V-type engines, it is associated with Bank 2. Bank 2 is the cylinder bank that does not contain cylinder number one.

On some inline engines, Sensor 2 may identify:

Always consult the vehicle’s service information. Sensor numbering is not universal, and Bank 2 is not automatically the driver or passenger side.

How a Knock Sensor Works

Most knock sensors contain a piezoelectric element. Engine vibration applies force to this element, causing it to generate a small electrical signal.

The PCM evaluates that signal alongside:

When the PCM identifies combustion knock, it can retard ignition timing to reduce cylinder pressure and protect the engine.

If Knock Sensor 2 produces a signal that is consistently too weak, the PCM may not be able to distinguish normal combustion from detonation on the monitored bank.

How the PCM Detects P0332

Detection strategies vary by manufacturer, but the PCM may set P0332 when:

Some vehicles may require the fault to occur during multiple drive cycles before illuminating the Check Engine Light.

P0332 Versus Related Knock-Sensor Codes

CodeDefinitionDiagnostic distinction
P0330Knock Sensor 2 Circuit MalfunctionGeneral Sensor 2 circuit fault
P0331Knock Sensor 2 Range/PerformanceSignal exists but behaves implausibly
P0332Knock Sensor 2 Circuit Low InputSignal remains below its expected threshold
P0333Knock Sensor 2 Circuit High InputSignal remains above its expected threshold
P0334Knock Sensor 2 Circuit IntermittentSignal drops out, spikes or returns

Your existing P0330 2JZ knock-sensor guide covers Sensor 2 replacement on that specific platform. P0332 should remain focused on determining why the signal voltage is consistently low.

How Serious Is the P0332 Code?

P0332 is generally considered a moderate fault.

The vehicle may continue running, but the PCM may no longer receive dependable knock information from Sensor 2. It may respond by:

The larger concern is genuine detonation occurring while the sensor signal is too weak to be evaluated correctly.

Stop driving if you hear severe pinging or knocking, especially when combined with overheating, low oil pressure or a flashing Check Engine Light.

Common Symptoms of P0332

Possible symptoms include:

Some vehicles may appear to run normally because the PCM substitutes conservative ignition settings.

Common Causes of the P0332 Code

Common P0332 causes include:

  1. Failed Knock Sensor 2
  2. Internally shorted sensor
  3. Signal wire shorted to ground
  4. Excessive signal-circuit resistance
  5. Open circuit producing an interpreted low signal
  6. Loose sensor connector
  7. Corroded connector terminals
  8. Spread or damaged terminals
  9. Water intrusion
  10. Coolant contamination
  11. Oil contamination
  12. Damaged wiring insulation
  13. Harness pinched against the engine
  14. Harness melted near the exhaust
  15. Incorrect knock sensor
  16. Low-quality replacement sensor
  17. Loose knock sensor
  18. Incorrect mounting torque
  19. Dirty sensor mounting surface
  20. Corrosion beneath the sensor
  21. Excessive thread sealant
  22. Poor engine ground
  23. Poor PCM ground
  24. Damaged PCM connector
  25. PCM software problem
  26. Internal PCM failure

Mechanical engine knock alone is less likely to create a low electrical input. However, actual engine condition should still be evaluated because knock protection may be reduced while the code is active.

Why Incorrect Sensor Torque Can Cause a Weak Signal

A knock sensor depends on controlled physical contact with the engine block.

If the sensor is too loose, vibration may not transfer into the sensing element correctly. This can reduce signal amplitude and contribute to P0332.

If the sensor is over-tightened, it may:

The mounting surface must also be:

Always use the manufacturer’s torque specification. “Snug enough” is not a published measurement, despite its continued popularity.

Why Corrosion and Contamination Matter

Knock sensors are often installed in areas exposed to:

Contamination may cause:

Some GM LS applications are known for collecting water around knock sensors mounted beneath the intake manifold. Other engine designs may develop coolant or oil contamination in similar enclosed locations.

Replace damaged components and repair the source of the contamination.

Common P0332 Scan-Tool Patterns

Knock Sensor 2 Activity Remains Low

The scan tool may show little or no Sensor 2 activity while Sensor 1 responds normally.

Possible causes include:

Sensor 2 Differs Greatly From Sensor 1

When the engine uses two comparable sensors, graph both channels under the same conditions.

A consistently weaker Sensor 2 signal may indicate:

Normal differences may exist because sensor locations and engine-block construction affect vibration transfer.

Knock Retard Remains at Zero

No recorded knock retard may result from:

Zero knock retard is not enough to condemn the sensor. Review the complete signal and manufacturer test procedure.

Ignition Timing Remains Retarded

The PCM may use conservative timing because it cannot trust the Sensor 2 circuit.

Drivers may notice:

P0332 Returns Immediately

If the code returns immediately after clearing, suspect a persistent electrical fault such as:

How to Diagnose the P0332 Code

Step 1: Scan All Modules

Record:

Check for additional codes involving:

Do not clear the information until it has been recorded.

Step 2: Confirm Sensor 2 and Bank 2

Use the manufacturer’s service information to identify:

Inline engines may use two sensors without having two cylinder banks. Follow the manufacturer’s naming convention.

Step 3: Inspect for Engine Noise

Listen for:

P0332 identifies a weak electrical signal, not the source of an audible engine knock.

For a symptom-based diagnosis, use Engine Knocking Noise: What It Means.

Step 4: Inspect the Sensor and Connector

Inspect Knock Sensor 2 for:

A connector can appear attached while one terminal makes poor contact. Check terminal tension, not just connector appearance.

Step 5: Verify the Sensor Part Number

Confirm that the installed sensor matches the exact application.

An incorrect sensor may:

When P0332 appears soon after sensor replacement, verify the part before taking the intake apart again. The least enjoyable repair is repeating one because the new part was wrong from the beginning.

Step 6: Verify Mounting Torque

Check:

Correct any installation problem before continuing.

Step 7: Inspect the Wiring Harness

Follow the circuit from the sensor to the PCM.

Look for:

Pay special attention to wiring beneath intake manifolds and near engine mounts.

Step 8: Check for a Short to Ground

With the appropriate modules disconnected, test whether the signal circuit is shorted to ground.

A short may be caused by:

Compare the results with manufacturer specifications.

Do not perform resistance testing on a connected controller circuit unless the service procedure specifically allows it.

Step 9: Check Circuit Resistance

Test continuity between Knock Sensor 2 and the PCM.

Inspect for:

A continuity beep does not prove the circuit can carry a clean low-level signal. Record the actual resistance and compare it with specifications.

Step 10: Check Grounds

Inspect:

Perform voltage-drop testing while the engine operates.

A poor ground can alter low-voltage sensor signals and create several unrelated codes.

Step 11: Compare Sensor 1 and Sensor 2 Data

Graph both knock-sensor channels during:

Do not deliberately create severe detonation.

If Sensor 1 responds normally while Sensor 2 remains consistently weak, focus on Sensor 2, its mounting and its circuit.

Step 12: Test the Sensor Waveform

Use an oscilloscope to evaluate signal amplitude and quality.

Look for:

Compare the waveform at:

If the signal is strong at the sensor but weak at the PCM, suspect wiring resistance, connector problems or circuit damage.

If the output is weak directly at the sensor after its mounting has been verified, the sensor may be defective.

Step 13: Test the PCM Input

Only investigate the PCM after verifying:

If a correct signal reaches the PCM terminal but scan data still reports low input, consider:

PCM replacement may require programming and security-system relearning.

Common P0332 Diagnostic Mistakes

Avoid these common mistakes:

P0332 tells you that the signal is low. It does not tell you where the voltage disappeared.

How to Fix the P0332 Code

Possible repairs include:

After completing repairs:

  1. Clear the stored codes.
  2. Start the engine and monitor both knock-sensor channels.
  3. Allow the engine to reach operating temperature.
  4. Verify reasonable ignition timing and knock-retard data.
  5. Reproduce the freeze-frame conditions.
  6. Complete the required drive cycle.
  7. Rescan for pending and stored codes.

Estimated P0332 Repair Costs

RepairTypical estimated cost
Professional diagnosis$100–300
Connector or terminal repair$75–300
Wiring repair$100–600
Knock Sensor 2 replacement$150–900
Intake-manifold removal for access$400–1,200+
Water- or coolant-intrusion repair$100–1,000+
PCM software update$100–300
PCM replacement and programming$800–2,500+

Sensor access can have a larger effect on cost than the price of the sensor itself.

Can You Drive With a P0332 Code?

Limited driving may be possible if:

Avoid driving if the vehicle has:

The PCM may reduce ignition timing while P0332 is active, but knock protection for the affected sensor area may still be limited.

Can a Bad Knock Sensor Cause P0332?

Yes. A failed or internally shorted Knock Sensor 2 can produce insufficient signal voltage.

However, the same code can be caused by:

Test the circuit before replacing the sensor.

Can Incorrect Torque Cause P0332?

Yes.

If the sensor is too loose, it may not receive enough engine vibration to generate the expected signal.

If it is too tight, the sensor may be damaged or its response may become distorted.

Use the manufacturer’s exact torque specification.

Can Water Under the Intake Manifold Cause P0332?

Yes.

Water, coolant or oil around the sensor can corrode its connector and increase circuit resistance.

Remove the contamination, replace damaged components and repair the source of the leak.

Can a Short to Ground Cause P0332?

Yes. A signal wire contacting ground can pull the knock-sensor voltage below the PCM’s expected threshold.

Inspect for damaged insulation, pinched wiring and incorrect repairs.

Does P0332 Mean the Engine Is Knocking?

No.

P0332 means the electrical signal from Knock Sensor 2 is too low. The engine may or may not be experiencing actual detonation.

An audible knock requires a separate mechanical and combustion diagnosis.

Related Pro Street Diagnostic Guides

Continue the diagnosis with these resources:

Final Thoughts

The P0332 code means the PCM is receiving an abnormally low signal from Knock Sensor 2.

The sensor may have failed, but wiring shorted to ground, excessive resistance, corrosion, contamination and incorrect mounting can produce the same result.

Begin by identifying Sensor 2 correctly. Inspect its connector and mounting, verify the part number and torque, then compare Sensor 1 and Sensor 2 data. Test the waveform at the sensor and PCM before replacing components.

P0332 is a low-input code, not a direct sensor conviction. Find where the signal becomes weak before issuing the parts-store sentence.

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