Plain English
What P0303 means for your Toyota Camry
Your Camry's ECM detected that cylinder 3 isn't firing properly - the crankshaft position sensor saw the rotational speed dip slightly each time cylinder 3 was supposed to combust. On the Camry four-cylinder engines, P0303 is most often a worn cyl-3 ignition coil or fouled plug. On the 2GR-FE V6, cyl 3 is at the front-bank passenger end and a coil failure is the typical cause.
🎯 Top Causes on the Toyota Camry
60%
#1 CAUSE
Cylinder 3 Ignition Coil Failure
Denso COP coils on 2AR-FE and 2AZ-FE Camrys fail between 80k-130k miles. The cyl-3 coil is the third from the timing-chain end and runs slightly cooler than cyl-1, so it often outlasts cyl-1 by 10-20k miles. Coil swap test: move cyl-3 to cyl-1 and see if misfire follows. Use Denso 90919-02258 OEM or NGK U5099 aftermarket.
OEM Coil
$80-$120
Aftermarket
$45-$70
w/Labor
$120-$280
25%
#2 CAUSE
Worn Iridium Spark Plug
Camry plugs (NGK IFR5T11 or Denso SK16HR11) are spec'd for 100k-120k miles. A plug worn open gap (target 0.043") raises firing voltage. On 2AZ-FE engines with oil consumption, cyl-3 plug often shows oil fouling - replace all four plugs as a set and address the underlying oil burning. Always use Toyota-spec iridium plugs.
Plugs (set 4)
$30-$60
V6 Plugs
$45-$90
w/Labor
$80-$220
15%
#3 CAUSE
VVT-i Variator Issue or Injector Clog
A stuck VVT-i (variable valve timing) cam-position actuator on the 2AR-FE can cause weird cylinder-specific timing problems and a P0303 that doesn't respond to coil/plug swaps. Other DTCs (P0011, P0014) usually accompany. Less commonly, a clogged cyl-3 injector causes the misfire - try Techron Concentrate Plus first, then swap injectors with cyl-2 to confirm.
VVT-i Actuator
$280-$500
Injector
$60-$140
w/Labor
$300-$600
🚗 Most Affected Camry Model Years
| Year | Engine | Primary Cause | Typical Mileage | Notes |
|---|---|---|---|---|
| 2010-2017 | 2.5L 2AR-FE | Coil pack | 80k-130k | Most common |
| 2007-2009 | 2.4L 2AZ-FE | Oil-fouled plug + coil | 90k-160k | Check oil-consumption TSB |
| 2018+ | 2.5L A25A-FKS | Coil | 60k-90k | Direct injection: carbon at 80k+ |
| 2007-2017 | 3.5L 2GR-FE V6 | Front-bank coil | 80k-130k | Cyl 3 is front-bank passenger end |
🔧 How to Diagnose P0303 on a Toyota Camry
- Swap the cyl-3 coil with cyl-2 (easy on the 4-cyl; on V6, cyl 3 is the front bank passenger end). Clear code, drive. Misfire follows = bad coil.
- Pull the cyl-3 plug and inspect. Replace all four as a set if mileage is over 80k. Gap to 0.043".
- If coil and plug check good, scan for VVT-related codes (P0011, P0012, P0014, P0015). Any active VVT code points to the cam actuator, not ignition.
Want a step-by-step walkthrough specific to your Toyota Camry? Run a $5.99 AI diagnosis report - we narrow the cause to your year, engine, and symptoms.
❓ Frequently Asked Questions
How serious is P0303 on a Camry?
Moderate. A steady CEL with P0303 is safe to drive a few miles to the shop. A flashing CEL means active misfire that will damage the catalytic converter within 100-200 miles - don't drive it. Cat replacement on Camry runs $800-$2200.
Why does P0303 come back after I replaced the coil?
Usually one of: (1) you replaced the coil with a cheap eBay knock-off that failed within weeks, (2) the spark plug is also worn, (3) the coil boot has carbon-tracked, or (4) the actual problem is the injector or VVT-i. Run a fresh coil-swap test with the new coil to confirm it's not the issue.
Which cylinder is cylinder 3 on a Camry?
On the 4-cylinder Camry (2AR-FE, 2AZ-FE, A25A-FKS), cyl 1 is at the timing-chain end (passenger side) and cyls go 1-2-3-4 toward the transmission. Cyl 3 is the second from the transmission end. On the 3.5L V6, cyl 3 is the passenger-side end of the front bank.
Can I drive my Camry with P0303 to the shop?
Yes if the check-engine light is steady, no more than a few miles. If the light is flashing, do not drive - have it towed or fix it on-site.
Is P0303 covered by the 2AZ-FE oil-consumption warranty?
Indirectly. If your 2007-2009 Camry 2AZ-FE qualifies for TSB T-SB-0094-11 (oil consumption), Toyota will perform a ring-replacement repair that resolves the fouled-plug misfires - including P0303. Bring documentation of both the oil consumption AND the P030X code.
See all P0303 causes (all vehicles) → · Related: Toyota VVT-i Actuator Rattle →