{"vehicle":{"id":"2027_jeep_grand-cherokee-l","year":2027,"make":"Jeep","model":"Grand Cherokee L"},"code":"P0300","generic":true,"description":null,"bulletins":{"as_of":"2026-10-19","count":4,"bulletins":[{"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"}],"url":"https://open.wenmarpro.com/makes/jeep/grand-cherokee-l/2027/bulletins?code=P0300"},"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-l/2027/codes/P0300","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."]}