2011–2014 Chrysler 300

2011-2014 Chrysler 300 — Check Engine Light / OBD2 Diagnosis

By Ray Delgado ✓ Certified Mechanic · Published Sep 21, 2026 · Updated Oct 14, 2026

🔧 Easy 15-30 minutes $25 DIY

Save $95 by doing it yourself! Shop cost: $120

Quick answer: Check Engine Light / OBD2 Diagnosis on a 2011–2014 Chrysler 300 is rated Easy and takes about 15-30 minutes. You'll need 2 tools for this job, and parts cost about $25. This guide walks you through the full job step by step, including the mistakes to avoid.

Quick Video Tutorial

Parts You Need

Total Cost

$25.00

Part Name	Part Number	Price	Buy
OBD2 scanner	—	$25.00	Amazon

About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.

💡 Pro tip: Order all parts at once to save on shipping

Step-by-Step Instructions

Follow these steps carefully

Flashing means stop; steady means scan

Flashing = active misfire — stop safely, shut the engine off. Steady = planned-scan fault. Note fuel smell, rough idle, or stalling; the most common faults here — EVAP leaks — often show no symptoms beyond the light.

Connect to the DLC left of the steering column

The 16-pin OBD-II connector is under the driver-side dash, left of the column. Ignition off; plug the scanner in straight — never force. Powers up but won't communicate? Check the accessory/cigarette-lighter fuse; confirm the key is fully ON, engine off.

Capture stored, pending, and permanent codes

Key ON, engine off; pull every code with freeze-frame. Expect P0456/P0442/P0455 EVAP leaks, P0330 knock-sensor faults, P0300-series misfires, P0420 catalyst codes. Pending codes matter — EVAP faults often fail the monitor once before maturing into a stored code.

🔧 Mechanic's note — Ray Delgado

I've learned to respect pending codes on the 300 — EVAP faults often fail the monitor once before maturing into a stored code. Don't dismiss a pending EVAP code as a fluke.

Work through the 300's pattern failures

EVAP: gas cap seal, then purge solenoid, vapor hoses, NVLD pump — a known failure point. P0330: inspect knock-sensor wiring for chafing first. Misfires: plugs, coils, connectors. P0420: rule out exhaust leaks ahead of the converter.

🔧 Mechanic's note — Tom Becker

I've seen Chrysler EVAP glitches fixed by a PCM reflash per a factory TSB — so if the hardware all tests good, ask the dealer about applicable updates before throwing another part at it.

Clear, complete a drive cycle, rescan

Clear only after verified repair; drive a cycle — cold start, city, highway, idle — tank 1/4 to 3/4 for the EVAP monitor. Rescan to confirm. EVAP codes can take days to reappear; same code back, re-test the NVLD pump.

All Done!

Test your repair before closing everything up. If something doesn't work right, double-check your steps.

⚠️ Common Mistakes to Avoid

• Replacing parts based on a code without checking wiring, connectors, or vacuum leaks
• Clearing codes before recording confirmed, pending, and permanent codes
• Using a scanner that cannot communicate with the vehicle protocol
• Treating a stored code as proof that the named sensor itself failed

Tools You'll Need

OBD-II scanner compatible with the vehicle Flashlight Notebook or phone for codes and freeze-frame data Safety glasses

Related Trouble Codes

P0300 Random/Multiple Cylinder Misfire Detected P0301 Cylinder 1 Misfire Detected P0171 System Too Lean (Bank 1) P0101 Mass Airflow Sensor Range/Performance P0174 System Too Lean (Bank 2) P0562 System Voltage Low P0302 Cylinder 2 Misfire Detected P0303 Cylinder 3 Misfire Detected

⚠️ Safety First!

• Informational DIY. EZ Car Fix is not a shop.
• A flashing check-engine light can indicate a damaging misfire; reduce load and seek professional service promptly.
• Never work under a vehicle supported only by a jack.
• Do not clear codes before recording them and the freeze-frame data.