The Lemon IndexOn Hyundai and Kia engines, the knock sensor detection system picked up vibration that can point to wearing connecting rod bearings. Full P1326 page
92 owner complaints · the #1 code Kia Optima owners name · 51% of Kia Optima complaints that name a code (every car: 2.6%)
Middle of 103,000 miles · most between 98,000 and 130,000 (31 owners gave it)
Kia Optima owners named P1326 in 92 complaints to the U.S. government (NHTSA), most often on the 2020, 2016 and 2015 model years, at a middle of 103,000 miles. The part they name most is the knock sensor (20 complaints). Complaints are owner reports, not proof of a defect.
Kia Optima model years that report P1326
Owner complaints naming P1326, by model year. Raw counts: years that sold more get more complaints, so this is each model year's record, not a failure rate.
Mileage when it happened
103,000 miles is the middle of what 31 owners entered. Half were between 98,000 and 130,000 miles.
The mileage on the complaint form, when the owner gave one.
What owners say caused it or fixed it
The most-named part is the knock sensor, in 20 of the 92 complaints (22%). 13 of those mention it being replaced or repaired, and 3 say the problem came back afterwards. Next: engine (replaced or rebuilt) (10), engine computer (ECM / PCM) (5) and engine software (a reflash) (4).
- Knock sensor20 complaints13 mention a repair or replacement, 3 of them say the problem came back
- Engine replaced or rebuilt10 complaints10 mention a repair or replacement, 1 of them says the problem came back · what Kia Optima owners paid
- Engine computer (ECM / PCM)5 complaints5 mention a repair or replacement · what owners paid
- Software update (reflash)4 complaints4 mention a repair or replacement, 1 of them says the problem came back
- Spark plugs3 complaints2 mention a repair or replacement · what owners paid
36 complaints mention a recall and 20 mention a warranty.
Counted from the owners' own words: a part counts when a sentence names it with a cause or repair word. What owners wrote, not a diagnosis. A shop should confirm the cause before replacing parts.
Symptoms owners describe with P1326
65% of these complaints say the check engine light came on. 5% say the Kia Optima had to be towed.
- Rattles or knocks50%46 of 92 complaints
- Loses power or goes into limp mode47%43 of 92 complaints
- Flashing check engine light37%34 of 92 complaints
- Stalls or shuts off15%14 of 92 complaints
- Shakes, runs rough or misfires11%10 of 92 complaints
- Uses or leaks oil10%9 of 92 complaints
Share of the complaints naming P1326 whose text also describes each problem. A complaint can describe more than one.
Codes owners report with it
P0011 2
Other codes named in the same Kia Optima complaints, and in how many.
Repair costs
Kia Optima engine replacement cost
Recalls on these Kia Optima years
- Engine · 2012 · issued 2020
An engine compartment fire can occur while driving. NHTSA 20V750000 - Engine · 2011, 2012, 2013, 2014 · issued 2017
Machining errors during the engine manufacturing process may cause premature bearing wear within the engine. NHTSA 17V224000
2 recalls for the same systems (engine) on the Kia Optima model years above. A recall for the same system isn't proof it's behind P1326. Recall work is free at any dealer: check a VIN at nhtsa.gov/recalls or with our VIN check.
Keep going
- P1326: meaning, causes and every car that reports it
- Kia Optima reliability by year
- 2020 Kia Optima problems and recalls
P1326 on other cars
Hyundai Sonata (90) · Hyundai Tucson (53) · Hyundai Santa Fe (52) · Kia Soul (38) · Kia Sorento (31) · Kia Sportage (22) · Kia Forte (10)
The details
How we count
We read every owner complaint in the NHTSA file whose text names this trouble code, and count the ones filed about this model (matched by the make, model and model year on the complaint). Mileage is what the owner entered on the form.
Parts: a complaint counts for a part when one of the owner's own sentences names that part together with a cause word (failed, bad, diagnosed, caused by, leaking ...) or a repair word (replaced, repaired, new, reprogrammed ...). "Came back" means the same complaint also says the problem returned or the repair didn't fix it. These are counts of what owners wrote, not a diagnosis, and one complaint can name several parts.
Complaints are reports, not proof of a defect, and most owners never file one. Popular models get more complaints, so the counts are not a failure rate. The code meaning is the standard SAE J2012 definition in our own words, or the carmaker's meaning where we verified it for that make.
What P1326 means
On Hyundai and Kia engines, the knock sensor detection system picked up vibration that can point to wearing connecting rod bearings. The car may go into limp mode. Owners are usually told to see a dealer, because this system was added during the brands' engine bearing campaigns.
Stop and fix now. Don't put it off. This can affect safety, stall the car or cause expensive damage.
- Early connecting rod bearing wear
- Faulty knock sensor or wiring
- Software (KSDS update)
Check the complaints yourself
NHTSA complaint numbers (search them at nhtsa.gov): 11776382, 11775414, 11774145, 11773169, 11768350, 11767635, 11766255, 11762688, 11752542, 11743902, 11742779, 11742694 and 80 more.
Quick answers
What does P1326 mean on a Kia Optima?
Knock Sensor Detection System (KSDS). On Hyundai and Kia engines, the knock sensor detection system picked up vibration that can point to wearing connecting rod bearings. The car may go into limp mode. Owners are usually told to see a dealer, because this system was added during the brands' engine bearing campaigns.
Which Kia Optima years have the most P1326 complaints?
In complaints to NHTSA, owners of the 2020 (18), 2016 (15), 2015 (13) Kia Optima named P1326 most (92 complaints in all, 2011–2020). Raw counts, not a failure rate.
What fixes P1326 on a Kia Optima?
Owners most often name the knock sensor (20 of 92 complaints), then engine (replaced or rebuilt) and engine computer (ECM / PCM). That's what owners wrote, not a diagnosis: have a shop confirm the cause with a scan and tests before replacing parts.
At what mileage does P1326 show up on a Kia Optima?
Owners who gave their mileage reported a middle of 103,000 miles; half were between 98,000 and 130,000 (31 owners).
Can I drive my Kia Optima with P1326?
Stop and fix now. Don't put it off. This can affect safety, stall the car or cause expensive damage.
Sources: NHTSA owner complaints that name P1326 on the Kia Optima, counted by The Lemon Index; NHTSA recalls; repair bills owners named. Meanings: SAE J2012 in our own words. Owner reports, not a diagnosis or repair advice for your car.