P0326: How to Diagnose & Fix — Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)
2 vehicles · 2 makes · $200-$1,200 repair
How to diagnose and fix P0326: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Hyundai Veloster · 2019–2021
Some naturally aspirated 2.0L Veloster owners report check-engine lights, rough running, and reduced-power behavior tied to knock sensor activity or engine protection logic. While not as notorious as older Hyundai engine campaigns, the symptom pattern is documented enough to appear in owner complaints and service discussions: the car may suddenly feel flat, limit RPM, or illuminate the MIL even when no obvious mechanical noise is present. In some cases the issue is sensor-related; in others it requires ruling out genuine detonation, wiring faults, or software sensitivity.
Common Symptoms
- check engine light
- reduced power
- engine feels flat or limited
- intermittent rough running
- RPM limited
How to Fix
Scan for knock-sensor and misfire-related codes, inspect harness routing and connector condition, and verify fuel quality and ignition system health. If no mechanical problem is found, dealers may update software or replace the knock sensor/harness as needed. Persistent knock-related faults should not be ignored because the ECU may be actively protecting the engine from perceived abnormal combustion.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Hyundai knock sensor assemblyOEMHyundai 39250-2E000
knock-sensor replacement after testing confirms a sensor/circuit fault and mechanical knock is ruled out Fitment/availability: Hyundai 39250-2E000 is cataloged for 2019-2021 Veloster with the naturally aspirated DOHC-MPI engine. Confirm …
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Sources for this issue (1)
Kia K5 · 2021–2025
The 2.5L Theta II engine in certain K5 models has experienced knock sensor faults and engine knock concerns. The knock sensor may trigger false positives or fail to detect actual detonation, causing the ECU to either retard timing unnecessarily (reducing power) or fail to protect against harmful knock. Kia issued a software update to improve knock detection logic, but some owners report persistent issues after the update.
Common Symptoms
- Check engine light with knock sensor codes
- Reduced engine power or sluggish acceleration
- Audible pinging or knocking under load
- Poor fuel economy from excessive timing retard
- Engine hesitation during acceleration
How to Fix
Visit a Kia dealer for the latest ECU software update (TSB SA508) that improves knock detection calibration — this is typically performed at no cost. If the knock sensor itself has failed, replacement costs $200-$400 including labor. Use only 87+ octane fuel as specified. If actual engine knock is present (metallic pinging under load), have the engine inspected immediately as the Theta II engine family has a known history of connecting rod bearing issues in earlier applications. Kia has extended warranty coverage on some Theta II engines.
Owner tips & cautions
- TipCheck if your VIN is covered under the Kia engine warranty extension. Many Theta II engines have extended coverage to 150,000 miles for knock-related failures.
- TipRequest the latest ECU calibration update at every service visit. Kia has released multiple updates to improve knock detection and engine protection logic.
Find P0326 by make
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P0326 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 P0326 mean?
P0326 stands for "Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)." P0326 is a generic powertrain code indicating the engine computer detected that the knock sensor 1 (bank 1) signal is outside its expected range or performing improperly. The knock sensor listens for engine 'knock' (pre-ignition/detonation) so the PCM can retard timing to protect the engine; an out-of-range signal means the computer can no longer rely on it. This usually causes reduced performance and fuel economy and, if knock goes undetected, possible long-term engine wear.
What are the most common causes of P0326?
The most common causes of P0326 are: Faulty knock sensor, Damaged knock sensor wiring or connector, Corrosion or poor contact at the sensor, Engine mechanical noise mimicking knock, Loose sensor mounting / incorrect torque, Wiring shorted or open to the PCM, PCM fault (rare). The specific cause varies by vehicle.
How much does it cost to fix P0326?
Repair costs for P0326 range from $200 to $1,200, depending on the vehicle and root cause.
Which vehicles are affected by P0326?
Au7o has documented P0326 across 2 vehicle models from 2 manufacturers: Hyundai, Kia.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.