P0325 means the ECU sees an out-of-range voltage on the bank 1 knock sensor circuit. Without valid knock data the ECU defaults to conservative ignition timing, so you lose power and fuel economy.
DTC/P0325·Chevrolet
P0325 on Chevrolet: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Chevrolet
P0325 on a Chevrolet means the ECU sees an out-of-range voltage on the bank 1 knock sensor circuit. Without valid knock data the ECU defaults to conservative ignition timing, so you lose power and fuel economy.
Repair cost on Chevrolet€117 - €2080
What does P0325 mean on a Chevrolet?
Chevrolet Silverado
1999-2013GM LS-series V8 (4.8, 5.3, 6.0) with knock sensors mounted in the lifter valley under the intake manifold. Failures from coolant seepage past the sensor O-rings are so common GM sells a full replacement kit (12601822) with new sensors, harness, and grommets.
What causes P0325 on a Chevrolet?
Beyond the generic causes listed on the main P0325 page, these are the Chevrolet-specific patterns we see most often:
Chevrolet SilveradoCoolant intrusion from failed valley cover or intake gaskets shorting the sensors
Chevrolet SilveradoSub-harness insulation breakdown from decades of heat exposure
Chevrolet SilveradoOriginal AC Delco sensors typically fail between 160,000 and 200,000 km
How to diagnose P0325 on a Chevrolet with OBD2
Follow these steps to pinpoint the root cause of P0325:
- Scan the ECU and record freeze frame (RPM, load, coolant temp) at the moment the code set
- Visually inspect the knock sensor connector and pigtail for corrosion, oil, coolant or chafing
- Measure sensor resistance with a multimeter: piezo types read around 90-100 kΩ or effectively open; check against the factory spec for the specific engine
- Backprobe the signal and ground wires at the ECU connector and check continuity and shield integrity to the sensor
- With the scan tool live-reading knock voltage or knock counts, tap the block near the sensor with a small wrench to confirm the ECU sees a response
- If the sensor and wiring pass, remove the sensor, clean the mounting boss free of paint and rust, and torque to spec (typically 20-25 Nm for Toyota, ~20 Nm for GM LS)
- Clear the code and drive under load (moderate acceleration, 2,500-4,000 RPM); if P0325 returns immediately with the sensor and harness confirmed good, suspect the ECU input
How much does P0325 cost to fix on a Chevrolet? (EUR)
Estimated repair costs on a Chevrolet (Chevrolet parts and labour typically run 30% above the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0325 on Chevrolet
These codes commonly cluster with P0325 on Chevrolet vehicles:
FAQ: P0325 on Chevrolet
Will P0325 damage my engine if I keep driving?
Not on its own. With no valid knock signal the ECU pulls timing as a safeguard, so detonation is unlikely on decent fuel. The risk is that real knock could occur without being detected. Fix it within a few weeks, not months, and stay on 95 RON or higher in the meantime.
Why did P0325 come back after I replaced the knock sensor?
Nine times out of ten it's the harness, connector, or a cheap aftermarket sensor. Denso, Bosch, and NTK OEM units are worth the extra €20-€40, especially on Toyota 1MZ/2GR V6s and GM LS engines where generic sensors often fail within a year.
Can bad fuel cause P0325?
Low-octane fuel causes real knock, which usually sets P0324, P0327 or P0328, not P0325. P0325 is a circuit fault, meaning voltage out of range. If you filled up with cheap fuel and the light came on, scan it before assuming the sensor is bad.
How hard is it to replace the knock sensor myself?
On a 4-cylinder with the sensor on the side of the block (Civic R18, most Mazdas), it's a 30-minute job with a 10mm socket and an extension. On a V6 or V8 with the sensor in the lifter valley (Toyota 2GR, GM LS, BMW N52), plan a full day and budget for new intake manifold gaskets.
Does P0325 fail an MOT or emissions inspection?
Yes. In most EU countries and US states an active MIL is an automatic fail, regardless of the specific code. Readiness monitors also won't set until the code is cleared and a full drive cycle is completed, so don't clear it right before your inspection.
Looking for the full P0325 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0325 guideSkanyx · Chevrolet
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