P0327: How to Diagnose & Fix — Knock Sensor 1 Circuit Low Input (Bank 1)
7 vehicles · 3 makes · $250-$7,500 repair
How to diagnose and fix P0327: 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.
Kia Sorento · 2011–2019
The Theta II 2.4L and 2.0T GDI engines in 2011-2019 Sorentos can experience catastrophic engine seizure due to machining debris left in the crankshaft oil passages during manufacturing. Metal shavings restrict oil flow to rod and main bearings, causing premature bearing wear and eventual engine lock-up. Over 340,000 Sorentos were included in NHTSA Recall 17V-224. Kia extended the powertrain warranty to 10 years/120,000 miles for affected vehicles and deployed the Knock Sensor Detection System (KSDS) software update to detect early bearing deterioration.
Common Symptoms
- Engine knocking or ticking noise that worsens over time
- Oil pressure warning light illuminated
- Metal shavings found in oil during changes
- Sudden engine stall while driving
- Excessive oil consumption (more than 1 qt per 1,000 miles)
- Check engine light with bearing-related codes
How to Fix
Check VIN eligibility for extended warranty (10 years/120,000 miles). Have dealer perform KSDS software update to detect early bearing failure. If engine is knocking, dealer will perform oil consumption test and bearing inspection. Complete engine replacement required if bearings are scored. Dealer replaces with updated long block assembly under warranty if eligible.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Owner tips & cautions
- WarningIf you hear any knocking, stop driving immediately. Continued operation with failing bearings causes catastrophic damage that may not be covered if engine locks up completely
- TipCheck your VIN at owners.kia.com/recalls - even if past the original warranty, the extended 10yr/120k warranty applies to Theta II bearing failures
- TipUse 0W-20 full synthetic oil and change every 5,000 miles to maximize bearing life. Pennzoil Platinum or Mobil 1 are frequently recommended on KiaForums
Sources for this issue (3)
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.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
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.
GMC Sierra 1500 · 2000–2006
The 4.8L, 5.3L, and 6.0L Vortec engines used in early GMT800 Sierra trucks place the knock sensors in wells beneath the intake manifold, where water can collect and corrode the sensors or harness. Owners frequently report recurring check-engine lights, timing retard, and reduced power, especially after washing the engine bay or driving in wet conditions. GM issued service information addressing knock sensor corrosion and revised sealing practices.
Common Symptoms
- check engine light
- reduced power
- poor acceleration
- intermittent spark retard
- codes return after rain or washing
- rough running under load
How to Fix
Diagnosis involves scanning for knock sensor circuit codes, checking freeze-frame data, and inspecting the sensor wells and sub-harness under the intake for moisture or corrosion. Proper repair is replacement of both knock sensors and the harness, cleaning the valley area, and resealing the intake and sensor openings with the updated grommets/sealant procedure to prevent repeat failures.
Sources for this issue (1)
GMC Yukon XL · 2000–2006
Chevrolet Silverado 1500 · 2000–2006
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P0327 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 P0327 mean?
P0327 stands for "Knock Sensor 1 Circuit Low Input (Bank 1)." This code means the knock sensor on engine bank 1 sent a voltage signal that was lower than the expected range. The knock sensor is a small vibration microphone bolted to the engine block that listens for the 'pinging' of abnormal combustion (detonation), letting the computer retard ignition timing to protect the engine. A low-input reading usually points to an electrical problem — a fault in the sensor, its wiring, or connector — rather than actual knock. With the sensor compromised, the engine may run with safer, less efficient timing, causing slightly reduced power or fuel economy.
What are the most common causes of P0327?
The most common causes of P0327 are: Faulty knock sensor (Bank 1, Sensor 1), Damaged, shorted-to-ground, or corroded sensor wiring, Loose or corroded sensor connector, Improperly torqued/loose sensor mounting, Open or high-resistance signal circuit, Wiring shielding or grounding problem, Faulty engine control module (PCM) — rare. The specific cause varies by vehicle.
How much does it cost to fix P0327?
Repair costs for P0327 range from $250 to $7,500, depending on the vehicle and root cause.
Which vehicles are affected by P0327?
Au7o has documented P0327 across 7 vehicle models from 3 manufacturers: Chevrolet, GMC, Kia.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.