JEEP
09-023-26
Manufacturer communications
- Publication date
- 2026-09-25
- Received by NHTSA
- 2026-09-30
- NHTSA record numbers
- 11037570
Manufacturer summary
Original wording in English
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.
• 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.
Reported code forms
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
Jeep
P0300-00Random/Multiple Cylinder Misfire DetectedJeep
P0301-00Cylinder 1 MisfireJeep
P0302-00Cylinder 2 MisfireJeep
P0303-00Cylinder 3 MisfireJeep
P0304-00Cylinder 4 MisfireCheck vehicle applicability
A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Jeep | GRAND CHEROKEE | 2027 |
| Jeep | GRAND CHEROKEE | 2026 |
| Jeep | GRAND CHEROKEE L | 2027 |
| Jeep | GRAND CHEROKEE L | 2026 |