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P1326 on KIA OPTIMA

Q: "What does P1326 mean on a Kia Optima?"

"It points to knock sensor detection system / engine protection mode. FixIt found 89 NHTSA reports for this exact code/vehicle pair, so confirm with an enhanced scan and the OEM service procedure."

Q: "What are common symptoms of P1326 on Kia Optima?"

"Flashing Check Engine Light; Limp mode with reduced RPM or poor acceleration; Engine knock, stall, or no-restart after power loss."

Q: "What should I do first for P1326?"

"Check VIN-specific Hyundai/Kia campaigns, recalls, and warranty extensions first. Then inspect wiring/connectors, verify voltage/ground, and check VIN-specific recalls or campaigns where applicable."

Knock Sensor Detection System / engine protection mode

NHTSA Reports

Severity

High

Most Affected

2016, 2020, 2015

Crashes / Fires

0 / 1

Source: NHTSA Complaints Database · SAE J2012

Last reviewed: Jun 3, 2026 Last updated: Jun 3, 2026

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What P1326 Means on Your KIA OPTIMA

P1326 on Kia Optima points to knock sensor detection system / engine protection mode. FixIt matched 89 NHTSA owner reports for this exact code/vehicle pair, so use this page to prioritize the most likely symptoms, components, and next checks before replacing parts.

89 Kia Optima owners have reported this code/reference in NHTSA complaints across 2011-2020. Hyundai and Kia reports most often tie P1326 to flashing check-engine lights, limp mode, knock-sensor detection, and engine-failure risk.

Real KIA OPTIMA Owner Reports

Source: NHTSA Complaints Database

"My 2011 Kia Optimas engine light started flashing and the car lost all power and had no RPMS over 1000-2000. I took it to the dealership where I was told it had a code P1326 and they replaced a knock sensor. The same day that I picked my car up from them I was going down the interstate and it shut completely off and wo"

— 2011 KIA OPTIMA owner · ENGINE · Filed 06/22/2022

"I pulled out from a parking lot into traffic and not less then 5 seconds later the car sputtered once and then completely shut off in the middle of traffic. I was able to coast into the bike lane but was in fear that I would be rear-ended and possibly might incur injuries or harm would be caused to others due to the th"

— 2011 KIA OPTIMA owner · ENGINE · Filed 09/10/2021

"DRIVING ON INTERSTATE, OUT OF NOWHERE ENGINE LIGHT STARTED FLASHING AND ENGINE SEIZED, CAR LOST ALL MOMENTUM, HAD NO "GET UP AND GO" PUSHING ON THE GAS PEDAL DID NOTHING, GOING UP HILL WAS ALMOST IMPOSSIBLE. TOOK CAR TO LOCAL AUTO SHOP, THEY COULD HEAR SOME NOISE BUT WEREN'T SURE WHAT. PER INVOICE 7/26/19: CHECKED CODE"

— 2011 KIA OPTIMA owner · VEHICLE SPEED CONTROL,ENGINE,FUEL/PROPULSION SYSTEM · Filed 07/25/2019

"BOUGHT THE CAR JANUARY OF 2018.28 DAYS OF HAVING THE VEHICLE AND I GOT A FLAT TIRE AND COME TO FIND OUT MY STRUT WAS NEVER PROPERLY INSTALLED AND THATS WHAT POPPED MY TIRE.DAN OBRIEN TRIED TO DENY HAVING A WARRANTY TO FIX THE CAR SAYING IT WAS MY FAULT.IT WAS COVERED UNDER WARRANTY. I HAD TO BUY THE NEW TIRE. WHEN THE"

— 2011 KIA OPTIMA owner · ELECTRONIC STABILITY CONTROL (ESC),ENGINE,FUEL/PROPULSION SYSTEM · Filed 06/08/2019

"Driving on highway at about 60mph when the engine started knocking and the power decreased significantly. I pulled to the side of the road and called my day who came and brought his OBD 2 tester. The code was P1326 which is Knock Sensor. We had the car towed to a KIA dealer nearby and they updated the software. We pick"

— 2012 KIA OPTIMA owner · ENGINE · Filed 08/07/2024

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

'11

'12

'13

'14

'15

'16

'17

'18

'19

'20

Common Causes on KIA OPTIMA

Based on NHTSA complaint component analysis for this vehicle.

ENGINE 59.6%

POWER TRAIN,ENGINE 4.5%

POWER TRAIN,VEHICLE SPEED CONTROL,ENGINE 4.5%

ENGINE,FUEL/PROPULSION SYSTEM 3.4%

ELECTRICAL SYSTEM,ENGINE 3.4%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P1326 mean on a Kia Optima? ▾

It points to knock sensor detection system / engine protection mode. FixIt found 89 NHTSA reports for this exact code/vehicle pair, so confirm with an enhanced scan and the OEM service procedure.

What are common symptoms of P1326 on Kia Optima? ▾

Flashing Check Engine Light; Limp mode with reduced RPM or poor acceleration; Engine knock, stall, or no-restart after power loss.

What should I do first for P1326? ▾

Check VIN-specific Hyundai/Kia campaigns, recalls, and warranty extensions first. Then inspect wiring/connectors, verify voltage/ground, and check VIN-specific recalls or campaigns where applicable.