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Service bulletins for the 2021 Jeep Gladiator

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

700 on file from NHTSA, as of 2026-10-19.

About P0304 on the 2021 Jeep Gladiator: what the code means, and the bulletins and recalls about the same components.

By type

By component

By trouble code

Only bulletins with trouble code: P0304 are shown. Show all

Bulletins, newest first
09-011-252025-05-20. Service bulletin. ENGINE. "Misfire Diagnostic Trouble Codes (DTCs), Rough Idle, Valvetrain Noise Customers may experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0301 - Cylinder 1 Misfire. ● P0302 - Cylinder 2 Misfire. ● P0303 - Cylinder 3 Misfire. ● P0304 - Cylinder 4 Misfire. ● P0305 - Cylinder 5 Misfire. ● P0306 - Cylinder 6 Misfire. Customers may comment on one or more of the following: ● Rough idle. ● Valvetrain noise. "
18-060-242024-07-17. Service bulletin. POWER TRAIN. "Flash: Powertrain Control Module (PCM) Updates **Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P2463 - Particulate Filter Restriction - Soot Accumulation Bank 1. (EE Market Only)** ● P016F - Closed Loop Fuel Pressure Control At Limit - Pressure Too Low. ● P025C - Fuel Pump Module Control Circuit Low. ● P0300-00 - Multiple Cylinder Misfire. ● P0301-00 - Cylinder 1 Misfire. ● P0302-00 - Cylinder 2 Misfire. ● P0303-00 - Cylinder 3 Misfire. ● P0304-00 - Cylinder 4 Misfire. ● P0305-00 - Cylinder 5 Misfire. ● P0403-00 - EGR Control Circuit Open (Disabled Fault). ● P208B - Reductant Pump 1 Control Performance. ● P04DB - Crankcase Ventilation System Disconnected. ● P040F - EGR Temperature Sensor A-B Correlation. ● P225D - Nox Sensor 1/1 Performance - Signal Stuck Low. ● P0088 - Fuel Rail Pressure Too High. ● P0404 - EGR “A” Control Circuit Range/Performance. ● P20C6 - Reductant Heater 4 Control Circuit Performance. ● P0524 - Low oil pressure (during start up in cold ambient temps). ● P249C-00 - Excessive Time To Enter Closed Loop Reductant Injection Control. ● P02E8-00 - Diesel Intake Air Flow Position Sensor Circuit Low. ● P20FB-00 - Reductant Pump 2 Control Performance. ● P065A-00 - Generator System Performance. Customers may experience one or more of the following: ● Slow acceleration. ● Reduced vehicle speed & torque in high and 4 low. ● Poor cold idle stability. ● Poor idle quality with AC on. ● Excessive engine speed oscillations at tachometer red-line. ● Following a long key-on situation, poor cold start and idle stability. ● Cold hard start/extended crank. ● Block heater not providing a proper cold start and stable idle. ● High idle speeds at altitude when remote start is active. ● The cruise control and speed limited set speed doesn’t match the speedometer. It could be up to 2.5 kph (1.5 mph) difference. Other Software enhancements: ● Low speed engine idle improvements. ● Improved engine restart performance and torque response during low fuel level and/or hot ambient conditions. ● Corrects instances of vehicles restarting once SRC Inducement is active, and the mileage countdown has expired. ● Reduce engine delay during cold start garage shifts. ● Improve idle stability, Improvement of cold start and combustion stability after start during cold ambient temperatures. ● Eliminate turbocharger surge on tip-out. ● Eliminate idle oscillation in park and drive. ● Speedometer accuracy improvement(s). ● Cruise control updates. ● Battery durability improvements in hot ambient temperatures. This bulletin involves reprogramming the PCM with the latest available software."
18-002-22 REV. A2023-01-17. Service bulletin. SUSPENSION; BACK OVER PREVENTION; FUEL SYSTEM, DIESEL; EXTERIOR LIGHTING; FUEL SYSTEM, GASOLINE; ELECTRICAL SYSTEM; SERVICE BRAKES, HYDRAULIC. Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, a technician may find one or more of the following DTCs have been set: P016F - Closed Loop Fuel Pressure Control At Limit - Pressure Too Low. P025C - Fuel Pump Module Control Circuit Low. P0300-00 - Multiple Cylinder Misfire. P0301-00 - Cylinder 1 Misfire. P0302-00 - Cylinder 2 Misfire. P0303-00 - Cylinder 3 Misfire. P0304-00 - Cylinder 4 Misfire. P0305-00 - Cylinder 5 Misfire. P0403-00 - EGR Control Circuit Open (Disabled Fault). P208B - Reductant Pump 1 Control Performance. P04DB - Crankcase Ventilation System Disconnected. P040F - EGR Temperature Sensor A-B Correlation. P225D - Nox Sensor 1/1 Performance - Signal Stuck Low. P0088 - Fuel Rail Pressure Too High. P0404 - EGR ?A? Control Circuit Range/Performance. P20C6 - Reductant Heater 4 Control Circuit Performance. P0524 - Low oil pressure (during start up in cold ambient temps). P249C-00 - Excessive Time To Enter Closed Loop Reductant Injection Control. P02E8-00 - Diesel Intake Air Flow Position Sensor Circuit Low. P20FB-00 - Reductant Pump 2 Control Performance. P065A-00 - Generator System Performance. Customers may experience one or more of the following: Slow acceleration. Reduced vehicle speed&torque in high and 4 low. Poor cold idle stability. Poor idle quality with AC on. Excessive engine speed oscillations at tachometer red-line. Following a long key-on situation, poor cold start and idle stability. Cold hard start/extended crank. Block heater not providing a proper cold start and stable idle. High idle speeds at altitude when remote start is active. The cruise control and speed limited set speed doesn?t match the speedometer. It could be up to 2.5 kph (1.5 mph) difference. Other Software enhancements:Low speed engine idle improvements. Improved engine restart performance
09-013-20 REV. A2021-03-01. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM; ELECTRICAL SYSTEM:IGNITION:COIL:SPARK PLUGS; ENGINE. 3.6L Pentastar Upgrade Spark Plug Internal Crack This bulletin involves replacing all six spark plugs. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, a technician may find one or more of the following Diagnostic Trouble Codes (DTCs) have been set:P0301 - Cylinder 1 Misfire. P0302 - Cylinder 2 Misfire. P0303 - Cylinder 3 Misfire. P0304 - Cylinder 4 Misfire. P0305 - Cylinder 5 Misfire. P0306 - Cylinder 6 Misfire. Customers may also comment on the following:Rough running engine.
09-013-202021-03-01. Service bulletin. ENGINE; EQUIPMENT; ELECTRICAL SYSTEM. 3.6L Pentastar Upgrade Spark Plug Internal Crack This bulletin involves replacing all six spark plugs. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, a technician may find one or more of the following Diagnostic Trouble Codes (DTCs) have been set:P0301 - Cylinder 1 Misfire. P0302 - Cylinder 2 Misfire. P0303 - Cylinder 3 Misfire. P0304 - Cylinder 4 Misfire. P0305 - Cylinder 5 Misfire. P0306 - Cylinder 6 Misfire. Customers may also comment on the following: Rough running engine.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.