Knock Sensor 2 Circuit High Input (Bank 2)
P0333 indicates the knock sensor 2 circuit on bank 2 is reporting a voltage signal that is too high. The knock sensor detects engine predetonation (knock/ping) and sends this signal to the PCM; if the voltage is abnormally high, it suggests a circuit fault rather than actual knock events. This can cause the engine to run poorly or with reduced timing advance.
What You Might Notice
- Check Engine Light (MIL) illumination
- Audible knocking or pinging from engine compartment
- Pinging under acceleration
- Loss of engine power or performance
- Rough or irregular idle
Most Common Causes
- 1
Knock sensor circuit shorted to voltage
The knock sensor 2 wiring is shorted to a positive voltage source, causing the PCM to read an abnormally high signal. This is the most common electrical fault for a high input code.
- 2
Failed or faulty knock sensor
The knock sensor itself has failed internally and is sending a high voltage signal continuously. Knock sensors can degrade over time and lose their ability to properly signal engine conditions.
- 3
Damaged knock sensor connector
Corrosion, moisture, or physical damage to the knock sensor connector can cause poor contact and high resistance, resulting in abnormal voltage readings at the PCM.
- 4
Faulty PCM or electrical interference
In rare cases, the PCM itself may be defective, or electromagnetic interference from nearby wiring or components may be causing false high signals to be read.
How to Diagnose It
- 1
Check Knock sensor circuit shorted to voltage — The knock sensor 2 wiring is shorted to a positive voltage source, causing the PCM to read an abnormally high signal. This is the most common electrical fault for a high input code.
- 2
Check Failed or faulty knock sensor — The knock sensor itself has failed internally and is sending a high voltage signal continuously. Knock sensors can degrade over time and lose their ability to properly signal engine conditions.
- 3
Check Damaged knock sensor connector — Corrosion, moisture, or physical damage to the knock sensor connector can cause poor contact and high resistance, resulting in abnormal voltage readings at the PCM.
- 4
Check Faulty PCM or electrical interference — In rare cases, the PCM itself may be defective, or electromagnetic interference from nearby wiring or components may be causing false high signals to be read.
How to Fix It
- 1
Inspect and repair knock sensor wiring
Locate the knock sensor 2 circuit on bank 2 and inspect the wiring harness for pinches, abrasions, corrosion, or signs of shorts to voltage. Repair or replace any damaged wiring. Use a multimeter to verify the circuit is not shorted to power.
- 2
Replace knock sensor 2
Remove the faulty knock sensor from bank 2 using the appropriate socket and install a new OEM or quality aftermarket knock sensor. Ensure the sensor is properly torqued and the connector is fully seated before testing.
- 3
Clean or replace knock sensor connector
Disconnect the knock sensor connector and inspect for corrosion or damage. Clean the terminals with electrical contact cleaner and a soft brush. If the connector is damaged, replace it with a new connector assembly and reseat all connections.
- 4
Test PCM and verify no interference
If the above steps do not resolve the code, test the PCM with a diagnostic scanner to confirm the circuit is functioning correctly. Check for any aftermarket electronics or poorly grounded components that could be causing electrical noise.
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