{"vehicle":{"id":"2026_jeep_grand-cherokee","year":2026,"make":"Jeep","model":"Grand Cherokee"},"code":"P0301","generic":true,"description":null,"bulletins":{"as_of":"2026-10-19","count":7,"bulletins":[{"nhtsa_id":11038310,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2026-10-07","date":"2026-09-30","document_id":"09-013-26 REV. A","mfr_campaign":null,"component":"ENGINE","summary":"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.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11038310-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11038310-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11038310"},{"nhtsa_id":11037570,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2026-09-30","date":"2026-09-25","document_id":"09-023-26","mfr_campaign":null,"component":"ENGINE","summary":"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.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11037570-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11037570-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11037570"},{"nhtsa_id":11036358,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2026-08-26","date":"2026-08-20","document_id":"09-020-26","mfr_campaign":null,"component":"ENGINE","summary":"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.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036358-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036358-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11036358"},{"nhtsa_id":11036357,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2026-08-26","date":"2026-08-19","document_id":"09-017-26 REV. A","mfr_campaign":null,"component":"ENGINE","summary":"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.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036357-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036357-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11036357"},{"nhtsa_id":11036158,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2026-08-13","date":"2026-08-05","document_id":"09-017-26","mfr_campaign":null,"component":"ENGINE","summary":"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","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036158-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036158-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11036158"},{"nhtsa_id":11035049,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2026-07-18","date":"2026-07-10","document_id":"09-013-26","mfr_campaign":null,"component":"ENGINE","summary":"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.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035049-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035049-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11035049"},{"nhtsa_id":11033868,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2026-06-16","date":"2026-06-04","document_id":"18-058-26","mfr_campaign":null,"component":"POWER TRAIN","summary":"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 PCM and Transmission Control Module (TCM) with the latest available software.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11033868-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11033868-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11033868"}],"url":"https://open.wenmarpro.com/makes/jeep/grand-cherokee/2026/bulletins?code=P0301"},"related":{"components":[],"bulletins":[],"recalls":{"may_apply":true,"recalls":[],"lookup":{"nhtsa":"https://www.nhtsa.gov/recalls","tc":"https://wwwapps.tc.gc.ca/Saf-Sec-Sur/7/VRDB-BDRV/search-recherche/menu.aspx?lang=eng","maker":null}}},"url":"https://open.wenmarpro.com/makes/jeep/grand-cherokee/2026/codes/P0301","note":"The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.","attribution":["Contains information licensed under the Open Government Licence – Canada."]}