P0333 — Knock/Combustion Vibration Sensor B Circuit High

What Does P0333 Mean?

P0333 is a diagnostic trouble code indicating: Knock/Combustion Vibration Sensor B Circuit High. This code relates to the ignition system system. It has been reported in NHTSA complaints across 2 different vehicle models.

Engine misfires are detected by monitoring crankshaft rotational speed variations. Each cylinder's power stroke produces a characteristic acceleration pattern. When a cylinder fails to fire, the crankshaft decelerates during that cylinder's stroke. The ECM identifies which cylinder misfired and how often. P0313-P0399 codes cover extended misfire monitoring including lean misfire detection, knock-related ignition faults, and secondary ignition monitoring. A flashing check engine light during active misfires is an emergency — raw unburned fuel enters the catalytic converter, potentially destroying it.

Symptoms of P0333

⚠️ Check engine light on (may flash during active misfire)
⚠️ Engine misfiring — rough idle, stumbling, shaking
⚠️ Loss of power during acceleration
⚠️ Increased emissions and fuel consumption
⚠️ Catalytic converter damage if ignored
⚠️ Possible engine vibration at idle

Common Causes

🔍 Worn or fouled spark plugs
🔍 Faulty ignition coil
🔍 Vacuum leak causing lean misfire
🔍 Fuel injector issue (clogged, leaking, or electrical)
🔍 Low compression (worn rings, burned valve, head gasket)
🔍 Incorrect ignition timing

P0333 Reports by Year

2014

1

2024

1

2016

1

2021

1

Real Owner Reports

From NHTSA complaint database — actual owner descriptions.

"TOOK OUR 2005 TOYOTA TRUCK INTO THE TOYOTA DEALER FOR A CHECK ENGINE LIGHT P0333. THEY SAID THAT IT WAS A CABLE THAT WAS PREVIOUSLY REPLACED BY ANOTHER TOYOTA DEALER DUE TO RODENT DAMAGE. SINCE THE CAR ONLY HAS 2000 MILES SINCE THAT REPAIR AND A TOTAL MILEAGE OF 12,000 MILES WE FOUND IT UNBELIEVABL"
— Toyota Tacoma owner, 06/27/2014

"Some of the interior door light switches don't light @ night. I can probably take the door panel off & fix it... (buy bulbs)...? Door hinge on the gas cap breaks way to easily. Could fly off & hit someone\thing... Clunking sound coming from the rear end & I can't find where it's coming from... Gas "
— Toyota Tacoma owner, 11/03/2024

"RODENTS ATE WIRING HARNESS IN ENGINE COMPARTMENT, WHILE DRIVING IN THE CITY, THE TRAC AND CHECK ENGINE LIGHT CANE ON. I RETURNED HOME AND RETRIEVED ERROR CODE P0333 ON MY READER. I TOOK VEHICLE TO DOXON TOYOTA FOR SERVICE / REPAIR. THEY CONFIRMED CODE AND SAID THAT RODENTS HAD CHEWED KNOCK SENS"
— Toyota Tacoma owner, 01/01/2016

Source: NHTSA Complaints Database

Most Reported Vehicles for P0333

Based on NHTSA owner complaint data.

#	Vehicle	Reports
1	TOYOTA TACOMA
2	HONDA PILOT

P0333 Reports by Vehicle

Detailed NHTSA complaint analysis for each vehicle model.

TOYOTA TACOMA

3 NHTSA reports · Peak: 2005, 2008, 2014

Diagnostic Tips

Check misfire counters in Mode 6 data — identifies which cylinder(s) are misfiring most
Swap ignition coil to another cylinder — if misfire follows, coil is bad
Check spark plugs — worn electrode, fouled with oil or carbon, cracked insulator all cause misfires
Perform compression test on affected cylinder(s) — low compression means mechanical issue

Common Mistakes to Avoid

❌ Replacing coils without checking spark plugs — a worn plug will kill a new coil
❌ Ignoring a flashing check engine light — this means severe misfire that's damaging the catalytic converter NOW
❌ Replacing ignition parts when the misfire is caused by a vacuum leak or low compression

Frequently Asked Questions

What does a flashing check engine light mean?

A flashing CEL means severe, active misfire that risks catalytic converter damage. Pull over safely and reduce engine load. Do not rev the engine. Drive gently to a repair facility or have it towed. This is the only CEL condition that warrants immediate action.

Can misfires damage my engine?

Misfires themselves don't usually damage the engine, but they can destroy the catalytic converter ($1000-$3000). Severe misfires also dilute engine oil with raw fuel, reducing lubrication. Extended misfires should always be repaired promptly.

Why does my car misfire only when cold?

Cold misfires are often caused by slightly worn spark plugs (gap too wide for cold, dense air-fuel mixture), marginal ignition coils that work fine once warm, or small vacuum leaks that are more noticeable at cold idle RPM.

What To Do Next

Possible Fixes

🔧 Replace spark plugs
🔧 Replace ignition coil(s)
🔧 Repair vacuum leak
🔧 Clean or replace fuel injector
🔧 Engine mechanical repair (valves, rings, gasket)

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P0333: Knock/Combustion Vibration Sensor B Circuit High