P0333

P0333 means the Knock Sensor 2 circuit on Bank 2 is reading high — the signal voltage is pinned above the PCM's maximum threshold (typically over 4.5 V or saturated at the 5 V reference). This is a circuit-high code: shorted-to-power harness, internally shorted sensor, or a wiring fault that's pulling the signal line up to the reference voltage. Cheapest-first ladder: scan live data and watch the bank-2 knock counter at idle — a healthy system reads near 0 counts at idle and only ticks up under hard load; a pinned-high counter at idle (50 to 200 counts) means the PCM is reading constant noise as detonation. Backprobe the bank-2 signal wire with a DMM set to DC volts at key-on-engine-off — should read between 0 and 2.5 V (most systems use a 2.5 V DC bias on the signal line with the AC piezo signal riding on top); a reading above 4.5 V DC means the signal is shorted to the 5 V reference or to battery voltage. Unplug the sensor and recheck the voltage at the PCM connector — if it stays pinned high, the short is in the harness, not the sensor. Resistance-check the signal wire to chassis ground (should be over 1 megohm) and to battery positive (should be open circuit, infinite resistance); a short to power somewhere in the harness drops the resistance below 10 kohm. Expensive misdiagnosis caveat: on GM LSx platforms, a P0333 that appears immediately after intake gasket service is almost always a pinched harness under the intake manifold — the technician pinched the knock-sensor pigtail between the intake and the head when reinstalling; pop the intake back off and inspect before condemning either the sensor or the PCM.

Vehicle-specific patterns: 1999-2013 GM LSx V8 5.3/6.0/6.2L (Silverado, Tahoe, Suburban, Yukon, Escalade, Camaro, Corvette) throws P0333 from under-intake harness pinch points and from coolant intrusion creating an internal short in the connector pigtail; the GM-style pigtail repair kit addresses both. 2004-2010 Ford 4.6/5.4L Triton (F-150, Expedition, Mustang GT) throws P0333 from melted insulation on the rear-of-head bank-2 sensor wiring where it crosses the exhaust manifold. 2007-2015 Toyota 2GR-FE 3.5L V6 (Camry V6, Avalon, RAV4 V6, Sienna, Lexus ES350/RX350) throws P0333 from valley harness shorted to the intake plenum mounting boss. 2005-2012 Nissan VQ35DE (350Z, Altima, Maxima, Pathfinder) throws P0333 from a harness chafe where the knock pigtail rubs against an intake bolt and shorts to power. Estimated repair: $150 to $900.