Knock Sensor 1 Circuit (Bank 1 or Single Sensor)
What it means
The knock sensor is mounted on the engine block and picks up the vibration caused by abnormal combustion (knock). The engine computer has found a fault in the circuit of knock sensor 1 on bank 1, or the only knock sensor, and no longer trusts its signal, so it retards ignition timing as a precaution, costing power and fuel economy.
Related lights
Dashboard lights that may come on with this code.
Symptoms4
- Check engine light on.
- Noticeably weaker acceleration from retarded ignition timing.
- Slightly higher fuel consumption.
- Pinging or knocking sound from the engine under load in some cases.
Possible causes5
- Damaged or corroded connector or wiring between the sensor and the engine computer.
- Failed knock sensor.
- Heat-damaged wiring, especially on engines where the sensor sits under the intake manifold.
- Sensor tightened to the wrong torque or working loose.
- Engine computer fault (rare).
How to diagnose5
- Read the codes and check for a more specific one such as P0327 or P0328 that tells the type of fault.
- Find knock sensor 1 in the service manual and inspect the connector and visible wiring for corrosion or breaks.
- Measure sensor resistance and wiring continuity and compare them with the manufacturer specification.
- Confirm the sensor is tightened to the specified torque.
- If available, check the sensor signal on an oscilloscope while lightly tapping near it.
How to fix5
- Clean the connector and repair damaged wiring.
- Retighten the sensor to the correct torque if it is loose.
- Replace the knock sensor if it is proven faulty, cleaning the mounting surface.
- Replace the sensor harness if it is damaged under the intake manifold.
- Clear the codes, drive under moderate load and confirm the code does not return.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
In the Saudi market: SAR 100–900 (≈ USD 27–240)
Our prices come from the Saudi market, converted at a fixed rate (SAR 3.75 per USD). Prices in your country may differ a lot, so we show the cost level.
The cost is low when the fault is in the connector or visible wiring, and rises with a new sensor, especially if it sits under the intake manifold and that must be removed.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
Can I drive with this code?
Usually yes, because the computer retards timing to protect the engine. Use the recommended octane fuel and avoid heavy loads until it is repaired.
Why does knock sensor labor vary so much between cars?
On some engines the sensor is visible on the side of the block; on others it sits under the intake manifold, which takes hours of extra work to remove.
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