P0328 — Knock sensor A: circuit high

P0328 concerns knock-sensor A high circuit level. Some systems call it sensor 1/bank 1, but verify location with OEM data. The code alone does not prove actual knock or internal engine damage.

Affected system: Powertrain

Symptoms

• Engine lamp, sometimes without audible knock.
• Reduced power or increased consumption if the fallback strategy alters ignition timing.

Possible causes

• Open/shorted wiring or corroded connections; the effect depends on circuit bias.
• Damaged or incorrectly mounted sensor; consider ECM only after isolating the circuit.

What to check

• Record codes/freeze-frame; locate sensor A and its physical bank using OEM diagrams.
• Check mounting, contact surface and specified torque; do not overtighten as a test.
• Inspect corrosion and shielding; distinguish signal wires from designated shield/ground connections.
• With modules isolated as instructed, test opens/shorts and compare circuit bias against engine specifications.
• Evaluate signal with scan tool/scope under specified conditions; isolate sensor from wiring before diagnosing the high reading.

Also written as: P0328-00, P032800, PO328 (some scan tools add the fault-type byte, e.g. -00).