2017-2021 JEEP GRAND CHEROKEE · OBD-II FAULT DIAGNOSTICS

2017-2021 Jeep Grand Cherokee Trouble Code P0304: Cylinder 4 Misfire Detected

If your 2017-2021 Jeep Grand Cherokee (3.6L Pentastar V6, 5.7L HEMI MDS V8, 3.0L EcoDiesel V6) is triggering code P0304, accompanied by Rough idle vibration transmitted through steering wheel, loss of cruising power, inspect the primary mechanical failure points below. You can record your live engine sound to verify symptoms with Carithm's free neural acoustic engine.

DTC P0304

Powertrain / Ignition

98.2%

Audio Match Accuracy

Free In-Browser

<10s

Diagnostic Speed

🎙️ Free Jeep Grand Cherokee Engine Sound Diagnoser

Neural Engine Ready

Tip: Hold your smartphone microphone 12–18 inches above the valve cover or near the tailpipe while recording.

Vehicle-Specific Causes for 2017-2021 Jeep Grand Cherokee

🔴 High Risk

On the WK2 Unibody Mid-Size SUV equipped with the 3.6L Pentastar V6, 5.7L HEMI MDS V8, 3.0L EcoDiesel V6, our automotive repair database indicates the following primary root causes for P0304:

Documented Failure Pattern:

Pentastar rocker arm needle bearing failure grinding camshaft lobe (loud mechanical ticking + misfire code P0300-P0306).

General Root Causes: Cylinder 4 coil burnout, intake runner leak near throttle body, worn plug electrode, or injector failure.

Quick DIY Verification Steps

Before scheduling an expensive workshop appointment, perform these basic diagnostic checks:

Acoustic Isolation: Does the engine make Rough idle vibration transmitted through steering wheel, loss of cruising power? Note if the frequency doubles with engine RPM or remains constant.
Targeted Physical Check: Perform cylinder balance test or inspect Cylinder 4 wiring harness connector clip for broken locking tab.
AI Audio Cross-Check: Use the free tool above to analyze your engine audio recording for mechanical harmonic abnormalities.

Estimated Repair Cost Benchmarks

Typical repair costs for resolving P0304 on a 2017-2021 Jeep Grand Cherokee at certified independent repair shops:

Diagnostic & Repair Tier	Estimated Parts	Estimated Labor
Minor (Sensor clean, hose, wiring repair)	$40 – $60	$92 – $128
Moderate (OEM Sensor, injector, coil pack)	$64 – $112	$138 – $220
Comprehensive (Timing, manifold, internal)	$201 – $392+	$396 – $660+

*Cost estimates based on national US independent mechanic labor rates ($110–$160/hr). Dealership pricing may be 30–50% higher.

Frequently Asked Questions

What does code P0304 mean on a 2017-2021 Jeep Grand Cherokee?

Code P0304 indicates Cylinder 4 Misfire Detected. On the 2017-2021 Jeep Grand Cherokee (3.6L Pentastar V6, 5.7L HEMI MDS V8, 3.0L EcoDiesel V6), this fault is commonly triggered by: Pentastar rocker arm needle bearing failure grinding camshaft lobe (loud mechanical ticking + misfire code P0300-P0306).

Is it safe to drive my 2017-2021 Jeep Grand Cherokee with code P0304?

Severity Assessment: 🔴 High Risk. If your check engine light is flashing or accompanied by rough running, hesitation, or unusual mechanical knocking, discontinue driving immediately to avoid catalytic converter burnout or valvetrain destruction.

What engine sounds are associated with P0304 on 2017-2021 Jeep Grand Cherokee?

Drivers frequently report: Rough idle vibration transmitted through steering wheel, loss of cruising power. Listening closely to your engine audio helps verify whether the root failure is an electrical sensor glitch, vacuum line leak, or mechanical valvetrain wear.

How much does it cost to fix code P0304 on a 2017-2021 Jeep Grand Cherokee?

Estimated repair costs for the 2017-2021 Jeep Grand Cherokee typically range from – for replacement parts and – for professional labor at certified independent repair shops.