P0325 on Chevrolet: How to Diagnose & Fix
Knock Sensor 1 Circuit Malfunction (Bank 1)
1 Chevrolet model · 1 documented issue · $350-$900 repair
P0325 on Chevrolet by model: symptoms, diagnosis and fix
On 4.8L, 5.3L, and 6.0L GMT800 V8 trucks, the valley-mounted knock sensors and harness are prone to water intrusion from the cowl/intake area. Moisture corrodes the sensors or harness connectors, leading to false knock readings, a check engine light, and timing retard that can make the truck feel sluggish. This is one of the best-known early Silverado engine electrical issues and is heavily documented by owners and repair shops.
Common Symptoms
- check engine light
- reduced power or sluggish acceleration
- poor fuel economy
- intermittent spark knock timing retard
- engine runs normally but stores knock sensor codes
How to Fix
Diagnosis should confirm sensor circuit faults and inspect the harness and sensor wells for corrosion or standing water. Repair typically includes replacing both knock sensors, the sub-harness, intake gaskets, and the rubber seals/grommets, while cleaning the valley and addressing any water entry path. Using dielectric protection and updated sealing practices helps prevent repeat failures.
Sources for this issue (1)
P0325 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0325 mean on a Chevrolet?
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 Chevrolet it is documented across 1 model: Silverado 1500.
What are the most common causes of P0325?
The most common causes of P0325 are: 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). The specific cause varies by vehicle.
How much does it cost to fix P0325 on a Chevrolet?
Published repair estimates on Chevrolet range from $350 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0325 on a different make?
View P0325 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.