P0325 on Toyota
Knock Sensor 1 Circuit Malfunction (Bank 1)
P0325 on Toyota vehicles indicates knock sensor 1 circuit malfunction (bank 1). Au7o has documented this code across 1 Toyota model — most commonly on 4Runner. This code indicates a fault in the knock sensor 1 circuit on Bank 1. The knock sensor listens for the vibrations of detonation (pinging/spark knock) and lets the computer retard ignition timing to protect the engine. When the sensor's signal is missing, out of range, or the circuit is open/shorted, P0325 sets. With knock detection compromised, the computer may run more conservative timing, causing reduced power and slightly lower fuel economy, and the engine is less protected against damaging knock. Typical repair costs on Toyota range from $150 to $900, depending on the specific model and root cause.
Common Causes of P0325
- •Failed knock sensor
- •Corroded or loose knock sensor connector
- •Damaged, open, or shorted sensor wiring
- •Improperly torqued or loosely mounted sensor
- •Moisture or corrosion in the connector
- •Wiring harness chafing near the engine
- •Faulty PCM/ECM (rare)
P0325 on Toyota by Model
Toyota 4Runner(1 issue)
- 3.4L 5VZ-FE Knock Sensor & Sub-Harness Failure (P0325/P0330) — Brittle Harness Under Intake1996-2002
On the 3rd-gen 4Runner's 3.4L 5VZ-FE V6, the two knock sensors sit in the engine valley beneath the upper and lower intake manifolds, and their sub-wiring harness bakes over time. The harness insulation becomes brittle and crumbles, opening the circuit and setting P0325 (knock sensor 1 circuit) and/or P0330 (knock sensor 2 circuit). The ECU then pulls timing, hurting fuel economy and power. It is a very high-demand repair topic because the fix is buried under the intake, and because the ECU is extremely sensitive to sensor signal quality.
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View P0325 across all makes →Frequently Asked Questions
What does P0325 mean on Toyota?▼
P0325 stands for "Knock Sensor 1 Circuit Malfunction (Bank 1)." This code indicates a fault in the knock sensor 1 circuit on Bank 1. The knock sensor listens for the vibrations of detonation (pinging/spark knock) and lets the computer retard ignition timing to protect the engine. When the sensor's signal is missing, out of range, or the circuit is open/shorted, P0325 sets. With knock detection compromised, the computer may run more conservative timing, causing reduced power and slightly lower fuel economy, and the engine is less protected against damaging knock. On Toyota specifically, this code is documented across 1 model.
What causes P0325 on Toyota vehicles?▼
Common causes on Toyota: Failed knock sensor, Corroded or loose knock sensor connector, Damaged, open, or shorted sensor wiring, Improperly torqued or loosely mounted sensor, Moisture or corrosion in the connector. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0325 on a Toyota?▼
Repair costs on Toyota range from $150 to $900, depending on the specific model and root cause.
Which Toyota models have P0325 documented?▼
Au7o has documented P0325 on 1 Toyota model: 4Runner.