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OBD2.help›Powertrain›P0332

P0332

Knock Sensor B Circuit Low

The engine computer is not getting the normal signal from knock sensor B. This can be caused by a bad sensor, damaged wiring, or a problem in the engine control circuit. The engine may run poorly and may be at risk of knock damage if the issue is ignored.

SEV
3/5
DRIVE
CAUTION
DIY
$20–$120
SHOP
$150–$500

Quick answer

AI-CITATION READY

What it means

P0332 means the powertrain control module has detected a low-voltage or low-signal condition on the knock sensor B circuit. On most vehicles, this points to an electrical fault in the sensor circuit rather than an actual engine knock event. The PCM uses this input to adjust ignition timing, so a fault can reduce performance and fuel economy.

Can you drive with it?

With caution. You may be able to drive short distances, but the engine should be checked soon. If the engine is knocking, running rough, or losing power, avoid driving until repaired.

Most common causes

  • Faulty knock sensor B
  • Damaged, corroded, or loose wiring or connector in the knock sensor B circuit
  • Open or short in the knock sensor wiring harness

Typical repair cost

DIY usually runs $20–$120. Typical shop repair lands around $150–$500, depending on the root cause.

01 / Definition

P0332 means the powertrain control module has detected a low-voltage or low-signal condition on the knock sensor B circuit. On most vehicles, this points to an electrical fault in the sensor circuit rather than an actual engine knock event. The PCM uses this input to adjust ignition timing, so a fault can reduce performance and fuel economy.

02 / Drive status

With caution. You may be able to drive short distances, but the engine should be checked soon. If the engine is knocking, running rough, or losing power, avoid driving until repaired.

03 / Symptoms

  • Check engine light on
  • Reduced engine power
  • Poor acceleration
  • Lower fuel economy
  • Engine pinging or knocking under load
  • Rough running in some cases
  • Possible timing retard on scan data

04 / Causes

1Faulty knock sensor Bhigh
2Damaged, corroded, or loose wiring or connector in the knock sensor B circuithigh
3Open or short in the knock sensor wiring harnessmedium
4Poor engine ground or sensor ground problemmedium
5Engine mechanical knock or pinging from low-quality fuel, overheating, or carbon buildupmedium
6Failed PCM or internal circuit issuelow

05 / Diagnostic sequence

  1. 01Verify the code and check for related codes such as misfire, fuel trim, or sensor circuit codes.
  2. 02Inspect the knock sensor B connector and wiring for oil intrusion, corrosion, broken locks, heat damage, or rubbed-through insulation.
  3. 03Check that the sensor connector is fully seated and that pins are not bent, pushed out, or spread.
  4. 04Use a scan tool to look at knock sensor data, timing retard, and related live data while lightly tapping the engine or comparing readings between sensors if equipped.
  5. 05Test the sensor circuit with a multimeter according to the vehicle service manual, including reference voltage, signal, resistance, and ground checks.
  6. 06Inspect for engine conditions that can cause real knock, such as overheating, vacuum leaks, carbon buildup, incorrect spark plugs, or poor fuel quality.
  7. 07If wiring and sensor test good, check PCM power, ground, and control circuit integrity before suspecting the module.

06 / Repairs

1Repair damaged wiring, connectors, or terminals in the knock sensor B circuit$20–$150
2Replace the knock sensor B if it fails testing or has contamination or internal fault$50–$250
3Fix engine issues causing true knock, such as overheating, vacuum leaks, carbon buildup, or incorrect spark plugs$50–$600
4Diagnose and repair PCM power, ground, or internal driver faults if all external circuits test properly$150–$900

07 / Related codes

  • P0325
  • P0330
  • P0327
  • P0331
  • P0328
  • P0329

08 / FAQ

What does knock sensor B circuit low mean?

It means the engine computer is seeing a signal from knock sensor B that is lower than expected, or no valid signal at all.

Can a bad knock sensor cause poor performance?

Yes. The computer may reduce ignition timing to protect the engine, which can lower power and fuel economy.

Will low-quality fuel trigger P0332?

Low-quality fuel can cause actual knock, but P0332 usually points to an electrical problem in the sensor circuit.

Can I replace the knock sensor myself?

Sometimes yes, but on many engines it is difficult to access and requires intake or other components to be removed.

09 / Source and method

DATA BASIS
OBD-II REFERENCE + OBD2.HELP
METHOD
STATIC VALIDATION
SAFETY
INFORMATIONAL

This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.

Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.

Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.