P0325: Knock Sensor 1 Circuit Bank 1 or Single Sensor

What it means

A fault is detected in the circuit for knock sensor 1 on bank 1, or the single knock sensor. The code does not by itself establish whether the sensor or its wiring is at fault.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Knock sensor 1 detects engine vibration associated with combustion knock and sends a signal to the engine control module. The module uses that signal to adjust ignition timing; P0325 sets when it detects a fault in the sensor 1 circuit on bank 1, or the single-sensor circuit on engines with only one knock sensor.

Common causes

Most likely first.

1. Knock sensor failed
2. Sensor mounting bolt loose (sensor must be torqued correctly)
3. Wiring fault

Symptoms

• Check engine light on
• Power loss from defensive spark retard
• Increased fuel consumption
• Possible audible pinging under load

How to diagnose it

1. Read freeze-frame data and check for related knock-sensor or ignition codes to see when the circuit fault occurred.
2. Inspect knock sensor 1 on bank 1, or the single sensor, and its connector and wiring for damage, corrosion, looseness, or oil contamination.
3. Check that the sensor is mounted correctly and its fastener is tightened to the manufacturer's specification, since poor contact can affect the signal.
4. With the circuit diagram, check the sensor wiring for opens, shorts, and poor connections between the sensor and control module.
5. Test the sensor and circuit using the manufacturer's procedure to determine whether the sensor or wiring is at fault.

Common fixes

• Repair a loose or corroded sensor connector.
• Repair damaged wiring to knock sensor 1 on bank 1, or the single sensor.
• Mount the sensor correctly and tighten it to the manufacturer's specification.
• Replace the faulty knock sensor.

Can I keep driving?

You can usually drive gently for a short distance, but avoid heavy acceleration, high engine loads, and towing because the module may retard spark and knock protection may be reduced. Stop if you hear persistent pinging, which can damage the engine.