Knock Sensor Detection System (KSDS) Malfunction

What it means

This is a Kia-specific code; the same number can mean something different on other makes. On Theta II engines updated with KSDS software, the computer watches the knock sensor signal for a vibration pattern linked to internal engine bearing wear. If that pattern is found, the code is stored and engine power and RPM may be limited to protect the engine; see a Kia dealer without delay, because any wear gets worse with driving.

Models covered: Kia Theta II 2.0T and 2.4 engines fitted with the KSDS software update, mainly around 2011–2019 (e.g. Optima, Sorento, Sportage).

Related codes: P0325P0326P0328P0300P0520

Symptoms4

• The check engine light comes on or flashes while driving.
• Sudden loss of power, with RPM not rising above a set limit.
• A knocking sound from inside the engine in some cases, especially on acceleration.
• The car may seem normal after a restart while the code stays stored.

Possible causes5

• Early wear of the connecting rod or crankshaft bearings.
• Low, aged or wrong-viscosity engine oil.
• A faulty knock sensor, or a noisy signal from a damaged connector or wire.
• Incorrect knock sensor mounting after earlier engine work.
• Another source of mechanical vibration picked up by the sensor (less common).

How to diagnose5

1. Stop safely and check the oil level on the dipstick.
2. Do not just clear the code; book the approved KSDS inspection at a Kia dealer.
3. The dealer reviews codes and stored data, engine noise, oil pressure and oil condition.
4. An electrical fault is ruled out by checking the knock sensor, its wiring and mounting.
5. The dealer checks by VIN for any service campaign or extended warranty that applies to the car in its market.

How to fix5

1. Add the oil recommended by Kia if low, and drive gently to the dealer, or have it towed if there is a clear knock.
2. Repair the wiring or connector, or replace the knock sensor if it is the cause.
3. Apply the software update if the dealer recommends it.
4. Repair or replace the engine if the inspection confirms bearing wear.
5. Clear the codes after the repair and road test the car.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The range is wide because the cause may be a simple sensor or wear that needs a complete engine, and an engine costs more than the usual price table. Kia ran service campaigns and extended warranty for these engines in some markets, so ask the dealer about your car's coverage before paying.

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