P1325 Knock control at its limit (cylinder 1)
P1325 means: Knock control at its limit (cylinder 1). The knock sensor listens for engine knock. Drive gently and have the car checked soon. The most common repair costs about €80–160 in Estonia, depending on make and model. The most common cause: faulty or loose sensor.
What it means
The knock sensor listens for engine knock. If its signal is wrong, the computer retards the ignition to be safe and the engine loses power.
This is a make-specific code (VAG). The exact meaning can vary by model and year.
What you may notice
- Engine light on
- Less power
- Slightly higher fuel consumption
What could be wrong
- 1Faulty or loose sensor · Sensor replacement €80–160
- 2Sensor wire or connector · Sensor replacement €80–160
- 3Fuel octane too low · Fuel system check €45–90
- 4Real knock (carbon build-up, overheating) · Diagnosis and checks €45–90
Repair difficulty: Moderate
What you can check yourself
Fill up with the right octane fuel. The sensor is often on the block under the intake, so it may be hard to reach. You can check the simple things yourself, but the repair is best done in a workshop.
How we fix it
- We read the sensor on the diagnostic tool and compare it with other sensors
- We check the connector, supply and ground
- We repair the wiring or replace the sensor
Standard SAE description: Cylinder 1 Knock Control Limit Attained