Practical checks and shop questions for Knock circuit codes and OEM P1326; save evidence before replacing parts.
This is a non-invasive owner checklist, not an OEM repair procedure or permission to drive.
This reference supports the stated topic only. Model, model year, equipment, current rule or individual vehicle conditions may differ; check the original source before acting.
Read the Ford original: 1999 Powertrain Control/Emissions Diagnosis DTC descriptions Source date: document date not recorded; research checked: 2026-11-01.
Codes in this diagnostic topic
These codes share a system-level checklist, but their distinct numbers and meanings are shown below. A code here does not prove a particular vehicle has every listed fault. Use the exact code row and full scan.
| Code | Meaning | Vehicle scope |
|---|---|---|
| P0325 | Bank 1 knock-sensor circuit fault | Exact vehicle scope unverified |
| P0326 | Bank 1 knock-signal performance mismatch | Exact vehicle scope unverified |
| P0330 | Bank 2 knock-sensor circuit fault | Exact vehicle scope unverified |
| P0331 | Bank 2 knock-signal performance mismatch | Exact vehicle scope unverified |
| P1326 | Knock/KSDS-related fault; N-model water-intrusion branch | Hyundai |
| P1326 | KSDS knock-signal fault requiring the campaign diagnostic branch | Kia |
Save the evidence first
- Make, engine, year and complete code
- Engine noise, oil-pressure warning or limp mode
- Rain/carwash timing
- Current recall/campaign eligibility
Safe owner checks
- Stop if mechanical knocking, pressure warning or severe running problems occur.
- Record events; avoid repeated loaded driving to reproduce a knock.
Questions for a qualified technician
- Does the N-model water-intrusion bulletin fit, or does the Kia KSDS bearing-test branch fit?
- What diagnostic evidence supports sensor/wiring versus mechanical engine condition?
Common wrong turns
- Hyundai and Kia P1326 records cannot be merged into a universal sensor-replacement recipe.
Confirm the repair
- Verify the bulletin branch and symptoms after professional work.
Sources and scope
- Ford — 1999 Powertrain Control/Emissions Diagnosis DTC descriptions Document: date not recorded · Research checked: 2026-11-01
- Hyundai — 24-EM-010H Document: 2024-12 · Research checked: 2026-11-01
- Kia — PI1803Y/Z revision 2 Document: 2020-06-09 · Research checked: 2026-11-01
Research snapshot: 2026-11-01. Source documents may have newer revisions. Verify current instructions and VIN eligibility with the manufacturer.