P0325: Knock Sensor 1 Circuit Malfunction (Bank 1)
The knock sensor is a piezoelectric sensor that detects engine detonation vibrations (knock). P0325 indicates the ECM is receiving no electrical signal or has an open circuit.
Driveability & Safety Advisory
Drivable in safe mode, but ECM retards ignition timing, causing sluggish acceleration and reduced fuel efficiency.
Official Manufacturer TSB Advisories
Factory Condition: Rodents chew knock sensor sub-harness buried in engine block V-valley under intake manifold.
Physical Component Location & Service Access
Bolted directly into the center of the engine block underneath the intake manifold.
Electrical Specifications & Live PID Benchmarks
Scan Tool Live Data Targets
Digital Multimeter (DMM) Specs
Documented Model-Specific Case Studies
Root Cause: Mice chewed valley harness.
Verified Fix: Replace sub-harness.
Technician Inspection & Testing Workflow
Check harness continuity from ECM pin to knock sensor connector.
Inspect engine block valley for rodent nests.
Torque new sensor to exact factory spec (over-torquing ruins piezo crystal).
Recommended Diagnostic Tools & Verified Parts
BlueDriver Bluetooth Pro OBDII Scan Tool
Wireless sensor telemetry & enhanced diagnostics (Engine, ABS, Airbag). Delivers verified vehicle repair reports.
Autel AutoLink AL519 / AL319 OBD2 Scanner
Color screen standalone scanner. One-click I/M emissions readiness status, freeze-frame data, live DTC reset.
AstroAI Digital Multimeter 6000 Counts TRMS
Auto-ranging multimeter for measuring sensor pin resistance (ohms), live DC bias voltage, and circuit continuity per OEM specs.
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Cost Breakdown
Tools & Parts Matrix
Diagnostic Questions & Answers
Why is labor so expensive to change a $40 knock sensor?
Because on most V6 and V8 engines, the knock sensor is buried in the deep center valley of the engine block underneath the entire fuel rail and intake manifold.