2020 Chevrolet P0303: What It Means & Is It Safe to Drive?
P0303 on the 2020 Chevrolet: Cylinder 3 Misfire Detected. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
PowertrainHigh urgency
What this code means
The PCM has detected a misfire specifically on cylinder 3. Diagnosis follows the same steps as P0301—swap parts to the same position on a known-good cylinder to isolate the fault.
Common causes on the 2020 Chevrolet
- Worn or fouled spark plug on cylinder 3
- Failing ignition coil on cylinder 3
- Leaking or clogged fuel injector
- Low compression on cylinder 3
Symptoms
- Check Engine Light, often flashing under load
- Rough idle or shaking
- Loss of power, hesitation
Typical fixes
- Replace spark plug and coil on cylinder 3
- Test and replace fuel injector
- Compression test if ignition parts don't resolve it
Repair cost range
For a 2020 Chevrolet, repairs for P0303 typically fall between $150 and $900, depending on the root cause and labor rates in your area.
Known issues on Chevrolet
On GM's 5.3L AFM V8, cylinder 3 is an active cylinder so P0303 typically indicates a coil or plug failure rather than a lifter issue. On 3.5L V6 Impala and Malibu, check for intake manifold gasket failure at the cylinder 3 port first.
Most commonly affected models
Silverado 5.3L 2007–2014Tahoe 5.3L 2007–2014Impala 3.5L 2006–2013