P0333 Knock sensor 2 circuit fault on bank 2 (the side of the engine away from cylinder 1)

Knock sensor 2 circuit low input, bank 2

Monitor

A knock sensor fault mostly shows up as the check engine light, though the computer may pull timing to protect the engine; TroubleCodes.net lists hesitation or lack of power in some cases.

It gets more serious if:

  • Inspect soon: Get it inspected soon if the engine hesitates, loses power or pings under load, since the computer may be protecting the engine without its knock sensor.

Source: how we rate severity

P0333 in short

P0333 means the engine computer sees a fault in the knock sensor 2 circuit on bank 2. The usual causes are a damaged sensor, chafed or chewed wiring, or a loose sensor. It is often safe to drive short term, but get it checked if the engine pings or loses power.

A knock sensor listens for the vibration of spark knock, and the computer uses it to pull back timing and protect the engine. P0333 sets when the signal from the second sensor on bank 2 is outside the range the computer expects.

The sensor and its wiring cause most of these codes. Rodents chewing the wiring is a repeat story in Toyota Tacoma owner reports. TroubleCodes.net also notes that real engine knock can create a signal the computer reads as a fault.

General Motors has two bulletins on this code: one for a problem at the ECM X2 connector, and one where the park/neutral signal can leak into the knock sensor circuits when shifting from park. Subaru changed the knock sensor design on some models.

Most likely causes

  1. Failed or loose knock sensor

    Common general cause
    Why it ranks here
    TroubleCodes.net lists a defective sensor and an improperly tightened sensor first.
    What would change this
    Rises if the sensor tests out of specification or is loose. Falls if the sensor output is normal and the circuit is fine.
    How to test the knock sensor

  2. Damaged, shorted or chewed wiring

    Common general cause
    Why it ranks here
    Wiring faults including a short to positive are on the cause list, and two Toyota Tacoma owners report dealers finding rodent-chewed knock sensor wiring.
    What would change this
    Rises if the harness shows chew marks, chafing or a short on a continuity check. Falls if the wiring is intact and tests good.

  3. Debris or terminal problems at the ECM X2 connector (GM trucks and SUVs)

    Supported by vehicle data
    Why it ranks here
    GM bulletin 20-NA-207 covers P0333 on these vehicles and has the technician inspect the ECM X2 connector. The summary does not say what the repair is.
    What would change this
    Rises if the connector shows debris or a bad terminal. Falls if the connector is clean and tight.
    How to test the engine control module (ecm / pcm)

  4. Park/neutral signal leaking into the knock sensor circuit when shifting from park (GM)

    Supported by vehicle data
    Why it ranks here
    GM PIP5576 says P0333 can set when voltage from the transmission park/neutral signal circuit bleeds into the knock sensor circuits.
    What would change this
    Rises if the code sets as the transmission is shifted from park. Falls if the code is not tied to shifting.

  5. Real engine knock or noise

    Possible — needs testing
    Why it ranks here
    TroubleCodes.net says a genuine internal engine problem can produce vibration signals the computer reads as a sensor fault.
    What would change this
    Rises if the engine makes a knocking sound or other codes point to mechanical trouble. Falls if the engine sounds normal.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all stored codes and freeze-frame data. Note whether the code returned right after shifting from park, and whether other knock sensor codes are stored.

    Low riskTool: OBD-II scan tool

    • IfThe code comes back right after shifting out of park on a GM vehicle

      It meansAsk about the park/neutral bleed bulletin.

      Go to step 2

    • IfOther knock sensor codes (P0327 to P0332) are stored too

      It meansA shared wiring or connector fault is likely.

      Go to step 3

    • IfOnly P0333 is stored

      It meansInspect the sensor and wiring.

      Go to step 3

  2. Ask a dealer whether your VIN has an open bulletin for P0333 (GM connector inspection, Subaru knock sensor change).

    Low risk

  3. Look at the knock sensor, its connector and visible wiring for chew marks, chafing, corrosion and a loose sensor.

    Use cautionTool: flashlight, basic hand tools

    Warning:The sensors on many V6 and V8 engines sit under the intake manifold. Do not pull the manifold or work near hot parts yourself; let a shop do it.

  4. Test the sensor output and check continuity between the sensor and the computer.

    Best left to a shopTool: multimeter or scope, wiring diagram

    Warning:Back-probing computer connectors can damage terminals. Leave this to a shop.

Symptoms

  • Check engine light with no other change
  • Hesitation or reduced power Gets more serious: stop and have it checked.
  • Pinging or knocking under load Gets more serious: stop and have it checked.
  • Traction control light with the check engine light (reported on some Toyotas)

How to fix

  1. Check the engine bay for signs of rodents and look over accessible wiring and the connector for chew marks.

  2. Ask a dealer whether a bulletin applies to your VIN.

Parts and cost context

  • Knock sensor:The sensor is often cheap but can sit under the intake manifold, so labour is the main cost. Confirm the wiring first; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Chevrolet

  • 2014–2018 · Silverado 1500

    Supported by vehicle data

    GM PIP5576 says P0333 can set when shifting from park because of voltage on the park/neutral signal. Whether the bulletin is still current is not verified.

  • PIP5576Status unverified

    P0333 sets when shifting from park

    2014–2018silverado-1500, suburban · NHTSA 10145501

    The park/neutral signal can leak into the knock sensor circuits; if the information system does not isolate it, check the ECM X2 connector for debris or terminal problems.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

GMC

  • 2014–2020 · Yukon

    Supported by vehicle data

    GM bulletin 20-NA-207 covers an electrical concern at the ECM X2 connector for P0333. Whether the bulletin is still current is not verified.

  • 20-NA-207Status unverified

    MIL on, DTC P0333 set

    2014–2020yukon, yukon-xl, sierra-1500 · NHTSA 10209097

    Inspect for an electrical concern at the ECM X2 connector. The NHTSA summary names the code but not the repair.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Subaru

  • 2015–2017 · WRX

    Supported by vehicle data

    Subaru SIB 07-133-18 announces a knock sensor design change that may relate to P0333 on the 2.0L turbo models. Whether the bulletin is still current is not verified.

  • 07-133-18Status unverified

    Knock sensor design change, knock sensor codes including P0333

    2011–2017forester, wrx, crosstrek, legacy, outback · NHTSA 10153187

    Subaru announced a new knock sensor design for durability on these models; the check engine light with P0327, P0328, P0332 or P0333 may be related.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Toyota

  • P0332Knock sensor 2 circuit voltage low (bank 2)

    Other bank Possible — needs testing

    P0332 is the bank 1 counterpart for the second knock sensor. When both set, a shared wiring or computer connector fault is likely.

  • P0328Knock sensor 1 signal too high (bank 1)

    Same system Possible — needs testing

    P0328 is another knock sensor circuit code. A Honda Pilot owner reports P0328 and P0333 together with a two-bank harness failure.

All Ignition and engine position sensors codes

P0333 questions

Is P0333 the left or right sensor?

It is knock sensor 2 on bank 2, but which side of the engine that is depends on the engine layout. Check a wiring diagram for your vehicle.

Can rodents cause P0333?

Yes. Toyota Tacoma owners report dealers finding chewed knock sensor wiring behind P0333.

Sources and review

  1. P0333 trouble code overview — TroubleCodes.net
  2. NHTSA complaint ODI 10821880: Toyota Tacoma 2014, P0333 knock sensor wiring chewed by rodents — NHTSA Office of Defects Investigation
  3. NHTSA complaint ODI 10626222: Toyota Tacoma 2005, P0333 from rodent-damaged cable — NHTSA Office of Defects Investigation
  4. GM bulletin 20-NA-207 (NHTSA 10209097): MIL on, DTC P0333 set, inspect ECM X2 connector — General Motors
  5. GM PIP5576 (NHTSA 10145501): P0333 sets when shifting from park — General Motors
  6. Subaru SIB 07-133-18 (NHTSA 10153187): knock sensor design change — Subaru of America
Last reviewed
Written by
Saurabh K.
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