{"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,"replaces":null,"component":"ENGINE","mfr_system":null,"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","components":[{"id":"engine","name":"Engine","parent":null}],"codes":["P0300","P0301","P0302","P0303","P0304"],"topics":[],"vehicles":[{"make":"JEEP","model":"GRAND CHEROKEE","year_from":2026,"year_to":2027,"match":"exact","vehicle_ids":["2026_jeep_grand-cherokee","2027_jeep_grand-cherokee"]},{"make":"JEEP","model":"GRAND CHEROKEE L","year_from":2026,"year_to":2027,"match":"exact","vehicle_ids":["2026_jeep_grand-cherokee-l","2027_jeep_grand-cherokee-l"]}],"as_of":"2026-10-19","note":"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.","attribution":[]}