{"nhtsa_id":11036780,"type":"warranty_extension","type_name":"Warranty extension","date_added":"2026-09-03","date":"2026-07-27","document_id":"66D Combo Rev1","mfr_campaign":null,"replaces":null,"component":"ENGINE","mfr_system":null,"summary":"CUSTOMER SATISFACTION NOTIFICATION NORTH AMERICA Spark Plugs Reference: 66D The spark plugs insulator on approximately 48,000 of the above vehicles may break due to excessive cylinder pressure. This pressure can cause the spark plug's ceramic insulator to crack, leading to a rough-running engine. If this issue is not resolved promptly, the broken fragments can fall into the cylinder and cause internal engine damage.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036780-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11036780-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11036780","components":[{"id":"engine","name":"Engine","parent":null}],"codes":[],"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":[]}