P0303 · メーカー技術情報

RAM · 2026-10-07

Flash: Powertrain Control Module (PCM) Update Customers may experience a Malfunction Indicator Lamp (MIL) illumination, and the vehicle may exhibit SYMPTOM: or set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300-00 - Multiple Cylinder Misfire - in Active or Stored status set during cold start catalyst heating. ● P0301-00 - Cylinder 1 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0302-00 - Cylinder 2 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0303-00 - Cylinder 3 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0304-00 - Cylinder 4 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0305-00 - Cylinder 5 Misfire - in Active or Stored status…

RAM · 2026-10-07

Flash: Powertrain Control Module (PCM) Updates Customers may experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300-00 - Multiple Cylinder Misfire - in Active or Stored status set during cold start catalyst heating. ● P0301-00 - Cylinder 1 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0302-00 - Cylinder 2 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0303-00 - Cylinder 3 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0304-00 - Cylinder 4 Misfire - in Active or Stored status set during cold start catalyst heating. ● P0305-00 - Cylinder 5 Misfire - in Active or Stored status set…

DODGE · 2026-10-03

Flash: Ignition System Control Module (ISCM) Updates PCR9A Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **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. ● P0306-00 - Cylinder 6 Misfire.** NOTE: **The above DTCs are being set during cold starts.** This bulletin involves inspecting and possibly reprogramming the ISCM, TCM and PCM with the latest available software.

JEEP · 2026-09-30

Engine Runs Rough Customers may experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300-00 - Random/Multiple Cylinder Misfire Detected. ● P0301-00 - Cylinder 1 Misfire. ● P0302-00 - Cylinder 2 Misfire. ● P0303-00 - Cylinder 3 Misfire. ● P0304-00 - Cylinder 4 Misfire. Customers may also comment on the following: ● Engine runs rough. This bulletin involves replacing all four main chamber spark plugs.

JEEP · 2026-09-25

Umbrella Valve Seal Missing From Cylinder Head Cover Vehicle may exhibit a MIL-ON. SYMPTOM: Upon inspection the technician may find that one or more of the following Diagnostic Trouble Codes (DTCs) have set: ● P0300-00 - Random/Multiple Cylinder Misfire Detected. ● P0301-00 - Cylinder 1 Misfire. ● P0302-00 - Cylinder 2 Misfire. ● P0303-00 - Cylinder 3 Misfire. ● P0304-00 - Cylinder 4 Misfire. This bulletin involves inspecting for a missing umbrella valve seal on the underside of the cylinder head cover and, if necessary, replacing the cylinder head cover.

JEEP · 2026-08-20

Umbrella Valve Seal Missing From Cylinder Vehicle may exhibit a MIL-ON. SYMPTOM: Upon inspection the technician may find that one or more of the following Diagnostic Trouble Codes (DTCs) have set: ● P0300-00 - Random/Multiple Cylinder Misfire Detected. ● P0301-00 - Cylinder 1 Misfire. ● P0302-00 - Cylinder 2 Misfire. ● P0303-00 - Cylinder 3 Misfire. ● P0304-00 - Cylinder 4 Misfire. This bulletin involves inspecting for a missing umbrella valve seal on the underside of the cylinder head cover and, if necessary, replacing the cylinder head cover.

JEEP · 2026-08-19

Umbrella Valve Seal Missing From Cylinder Head Cover Customer may experience a MIL-ON and/or an indication of low engine oil level. SYMPTOM: Upon inspection the technician may find the following: 1. One or more of the following Diagnostic Trouble Codes (DTCs) have set: ● P0300-00 - Random/Multiple Cylinder Misfire Detected. ● P0301-00 - Cylinder 1 Misfire. ● P0302-00 - Cylinder 2 Misfire. ● P0303-00 - Cylinder 3 Misfire. ● P0304-00 - Cylinder 4 Misfire. 2. Engine oil level is low. IMPORTANT! If none of above symptoms are present, this TSB does NOT apply. This bulletin involves inspecting the engine oil level, possibly inspecting for a missing umbrella valve seal on the underside of the cylinder head cover and, if necessary, replacing the cylinder head cover.

JEEP · 2026-08-05

Umbrella Valve Seal Missing From Cylinder Head Cover Customer may experience a MIL-ON and/or an indication of low engine oil level. SYMPTOM: Upon inspection the technician may find the following: 1. One or more of the following Diagnostic Trouble Codes (DTCs) have set: ● P0300-00 - Random/Multiple Cylinder Misfire Detected. ● P0301-00 - Cylinder 1 Misfire. ● P0302-00 - Cylinder 2 Misfire. ● P0303-00 - Cylinder 3 Misfire. ● P0304-00 - Cylinder 4 Misfire. 2. Engine oil level is low. IMPORTANT! If none of above symptoms are present, this TSB does NOT apply. This bulletin involves inspecting the engine oil level, possibly inspecting for a missing umbrella valve seal on the underside of the cylinder head cover and, if necessary, replacing the cylinder head cover

RAM · 2026-07-22

GMET6 SO MIL Changes At Elevation Above 1,000 FT Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● 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. ● P0306-00 - Cylinder 6 Misfire. Customers may experience the following: ● Engine missing or running rough.

RAM · 2026-07-22

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **U0104-00 - Lost Communication With Cruise Control Module (NA Market Only) (In Active or Stored status). ● U0405-00 - Invalid Data Received From Cruise Control Module (NA Market Only) (In Active or Stored status). NOTE: Vehicles setting DTCs U0405-00 and U0104-00 may experience an inability to be cleared.** ● P06DD-00 - Engine Oil Pressure Control Circuit Performance/Stuck Off. ● P0073-00 - Ambient Air Temperature Sensor Circuit "A" High. ● P0071-00 - Ambient Air Temperature Sensor Performance. ● P2C90-00 - Crankcase Ventilation System - Hose "A" Disconnected. ●…

JEEP · 2026-07-10

Engine Runs Rough Customers may experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300-00 - Random/Multiple Cylinder Misfire Detected. ● P0301-00 - Cylinder 1 Misfire. ● P0302-00 - Cylinder 2 Misfire. ● P0303-00 - Cylinder 3 Misfire. ● P0304-00 - Cylinder 4 Misfire. Customers may also comment on the following: ● Engine runs rough. This bulletin involves replacing all four main chamber spark plugs.

FORD, LINCOLN · 2026-06-18

Some 2025-2026 Explorer/Aviator/Police Interceptor Utility non-hybrid vehicles built on 06-Feb-2025 and through 13-Dec-2025 may exhibit various drivability symptoms including a rough idle or hesitation shortly after refueling. These symptoms may also be accompanied by liquid fuel in the fuel vapor lines and fuel vapor canister as well as an illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0133, P0300, P0301, P0302, P0303, P0304, P0305, and/or P0306 stored in the powertrain control module (PCM). This condition may be due to an intermittently sticking fuel level vent valve on the fuel tank allowing fuel to enter the evaporative emissions system lines and evaporative emissions canister during refueling. If the customer states that the drivability symptoms…

DODGE · 2026-06-13

Flash: Powertrain Control Module (PCM) Updates Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician must find one or more of the following Diagnostic Trouble Codes (DTCs) have been set: ● P0300 - Multiple Cylinder Misfire. ● P0301 - Cylinder 1 Misfire. ● P0302 - Cylinder 2 Misfire. ● P0303 - Cylinder 3 Misfire. ● P0304 - Cylinder 4 Misfire. ● P0305 - Cylinder 5 Misfire. ● P0306 - Cylinder 6 Misfire. ● P0307 - Cylinder 7 Misfire. ● P0308 - Cylinder 8 Misfire. ● P0420 - Catalyst System Efficiency Below Threshold Bank 1. ● P0430 - Catalyst System Efficiency Below Threshold Bank 2. Customers may comment on or experience the following: ● A rough idle condition.

JEEP · 2026-06-10

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): ● **P0300 - Multiple Cylinder Misfire (Active or Stored status set during cold start catalyst heating). ● P0301 - Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating). ● P0302 - Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating). ● P0303 - Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating). ● P0304 - Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating). ● P0305-00 - Cylinder 5 Misfire (Active or Stored status set during cold start catalyst heating). ●…

JEEP · 2026-06-04

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one of the following Diagnostic Trouble Codes (DTCs): ● P1CEA - Boost Side Evap Purge System Performance. ● P0300-00 - Random/Multiple Cylinder Misfire Detected ● P0301-00 - Cylinder 1 Misfire ● P0302-00 - Cylinder 2 Misfire ● P0303-00 - Cylinder 3 Misfire ● P0304-00 - Cylinder 4 Misfire Customers may also experience one or more of the following: ● Engine RPM fluctuations at low vehicle speeds after extended idling. ● An ignition-off draw or battery drain condition. ● Sluggish engine performance and misfires. ● Engine knocking when the accelerator is pressed hard or quickly This bulletin involves inspecting and possibly reprogramming the…

MERCEDES-BENZ · 2026-06-03

Complaint Check engine light activated. Fault codes related to misfire on multiple cylinders stored. Possible fault codes listed below: P030004 - Combustion misfiring has been detected. There is an internal fault. P030100 - Combustion misfiring of cylinder 1 has been detected P030200 - Combustion misfiring of cylinder 2 has been detected P030300 - Combustion misfiring of cylinder 3 has been detected P030400 - Combustion misfiring of cylinder 4 has been detected P030500 - Combustion misfiring of cylinder 5 has been detected P030600 - Combustion misfiring of cylinder 6 has been detected P031600 - Combustion misfires were detected at engine start. Cause Under analysis Remedy Note: If the vehicle has a single cylinder misfiring or a constant misfire, diagnose the cause of this separately.…

FORD, LINCOLN · 2026-05-28

Some of the vehicles listed in the Model statement above may exhibit all of the following conditions: * Engine misfire condition * Illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0301, P0302, P0303, and/or P0304 stored in the powertrain control module (PCM)

RAM · 2026-04-30

Flash: Ignition System Control Module (ISCM) 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): ● P2C30-00 - Ignition Coil Primary Circuit Fuse A. ● P2C31-00 - Ignition Coil Primary Circuit Fuse B. ● P0300-00 - Multiple Cylinder Misfire. ● P0301-00 - Cylinder 1 Misfire Detected. ● P0302-00 - Cylinder 2 Misfire Detected. ● P0303-00 - Cylinder 3 Misfire Detected. ● P0304-00 - Cylinder 4 Misfire Detected. ● P0305-00 - Cylinder 5 Misfire. ● P0306-00 - Cylinder 6 Misfire. ● P0420-00 - Catalyst System Efficiency Below Threshold Bank 1. ● P0430-00 - Catalyst System Efficiency Below Threshold Bank 2. Customers may also comment on the following: ● Engine hesitates/misfires…

JEEP · 2026-04-18

Flash: Powertrain Control Module (PCM) Updates **Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs):** ● **P0300 - Multiple Cylinder Misfire - In Active or Stored status set during cold start catalyst heating. ● P0301 - Cylinder 1 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0302 - Cylinder 2 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0303 - Cylinder 3 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0304 - Cylinder 4 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0305 - Cylinder 5 Misfire - In Active or Stored status set during…

JEEP · 2026-04-18

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300 - Multiple Cylinder Misfire - In Active or Stored status set during cold start catalyst heating. ● P0301 - Cylinder 1 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0302 - Cylinder 2 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0303 - Cylinder 3 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0304 - Cylinder 4 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0305 - Cylinder 5 Misfire - In Active or Stored status set during cold…

JEEP · 2026-04-18

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0300 - Multiple Cylinder Misfire - In Active or Stored status set during cold start catalyst heating. ● P0301 - Cylinder 1 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0302 - Cylinder 2 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0303 - Cylinder 3 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0304 - Cylinder 4 Misfire - In Active or Stored status set during cold start catalyst heating. ● P0305 - Cylinder 5 Misfire - In Active or Stored status set during cold…

JEEP · 2026-04-17

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300 - Multiple Cylinder Misfire (Active or Stored status set during cold start catalyst heating). ● P0301 - Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating). ● P0302 - Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating). ● P0303 - Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating). ● P0304 - Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating). ● P0305-00 - Cylinder 5 Misfire (Active or Stored status set during cold start catalyst…

JEEP · 2026-04-17

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300 - Multiple Cylinder Misfire (Active or Stored status set during cold start catalyst heating). ● P0301 - Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating). ● P0302 - Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating). ● P0303 - Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating). ● P0304 - Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating). ● P0305-00 - Cylinder 5 Misfire (Active or Stored status set during cold start catalyst…

JEEP · 2026-04-17

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0301 - Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating). ● P0302 - Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating). ● P0303 - Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating). ● P0304 - Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating). ● P0305-00 - Cylinder 5 Misfire (Active or Stored status set during cold start catalyst heating). ● P0306-00 - Cylinder 6 Misfire (Active or Stored status set during cold start catalyst…

JEEP · 2026-04-16

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0300 - Multiple Cylinder Misfire (Active or Stored status set during cold start catalyst heating). ● P0301 - Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating). ● P0302 - Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating). ● P0303 - Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating). ● P0304 - Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating). ● P0305-00 - Cylinder 5 Misfire (Active or Stored status set during cold start catalyst…

JEEP · 2026-04-16

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0300 - Multiple Cylinder Misfire (Active or Stored status set during cold start catalyst heating). ● P0301 - Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating). ● P0302 - Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating). ● P0303 - Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating). ● P0304 - Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating). ● P0305-00 - Cylinder 5 Misfire (Active or Stored status set during cold start catalyst…

JEEP · 2026-04-16

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0300 - Multiple Cylinder Misfire (Active or Stored status set during cold start catalyst heating). ● P0301 - Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating). ● P0302 - Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating). ● P0303 - Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating). ● P0304 - Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating). ● P0305-00 - Cylinder 5 Misfire (Active or Stored status set during cold start catalyst…

JEEP · 2026-03-25

Flash: Ignition System Control Module (ISCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P2C30-00 - Ignition Coil Primary Circuit Fuse A. ● P2C31-00 - Ignition Coil Primary Circuit Fuse B. ● P0300-00 - Multiple Cylinder Misfire. ● P0301-00 - Cylinder 1 Misfire Detected. ● P0302-00 - Cylinder 2 Misfire Detected. ● P0303-00 - Cylinder 3 Misfire Detected. ● P0304-00 - Cylinder 4 Misfire Detected. ● P0305-00 - Cylinder 5 Misfire Detected. ● P0306-00 - Cylinder 6 Misfire Detected. ● P0420-00 - Catalyst System Efficiency Below Threshold Bank 1. ● P0430-00 - Catalyst System Efficiency Below Threshold Bank 2. Customers may also comment on the following: ●…

DODGE · 2026-03-21

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0300-00 - Multiple Cylinder Misfire - in Active or Stored status set during engine warm up period. ● P0301-00 - Cylinder 1 Misfire - in Active or Stored status set during engine warm up period. ● P0302-00 - Cylinder 2 Misfire - in Active or Stored status set during engine warm up period. ● P0303-00 - Cylinder 3 Misfire - in Active or Stored status set during engine warm up period. ● P0304-00 - Cylinder 4 Misfire -in Active or Stored status set during engine warm up period. ● P0305-00 - Cylinder 5 Misfire - in Active or Stored status set during engine warm up…

JEEP · 2026-03-13

Not applicable to vehicles built for US market. Fuel Injector Leak Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P1336-00 - Multiple Cylinder Misfire. ● P1337-00 - Cylinder 1 Misfire. ● P1338-00 - Cylinder 2 Misfire. ● P1339-00 - Cylinder 3 Misfire. ● P1340-00 - Cylinder 4 Misfire.** ● 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. Customers may also comment on one or more of the following: ● Unstable idle. ● Abnormal engine noise. , Diagnostic section, Repair Procedure, additional Claims Data Note, Special Tool and Reading Defects…