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Service bulletins for the 2018 Jeep Grand Cherokee

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.

447 on file from NHTSA, as of 2026-10-19.

About P0456 on the 2018 Jeep Grand Cherokee: what the code means, and the bulletins and recalls about the same components.

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By component

By trouble code

Only bulletins with trouble code: P0456 are shown. Show all

Bulletins, newest first
18076232023-08-21. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); POWER TRAIN; ELECTRICAL SYSTEM. Flash: Powertrain Control Module (PCM) Updates Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find one or more of the following Diagnostic Trouble Codes (DTCs) have been set: ? **P0441 - EVAP Purge System Performance.** ? P0456 - EVAP System Small Leak. NOTE: If DTC P0456 is present use the wiTECH Small Leak Verification test (SLVT) to determine if a leak is present in the system. ? P06EF - Engine Restart Performance. This bulletin involves reprogramming the PCM with the latest available software.
18048232023-05-30. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. wiTECH Small Leak Verification Test (SLVT) - P0456-EVAP SYSTEM SMALL LEAK
18094192022-09-15. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find one or more of the following (DTCs) have been set:P06EF - Engine Restart Performance. P0456 - EVAP System Small Leak.If DTC P0456 is present use the wiTECH Small Leak Verification test (SLVT) to determine if a leak is present in the system. P0300 - Multiple Cylinder Misfire. P0301 - Cylinder 1 Misfire. P0302 - Cylinder 2 Misfire. P0303 - Cylinder 3 Misfire. P0304 - Cylinder 4 Misfire. P0305 - Cylinder 5 Misfire. P0306 - Cylinder 6 Misfire. In addition, customers may experience the following condition:Engine will auto stop and will not auto restart or the engine will auto start and this will result in a misfire, requiring customer to shift into park and manually restart vehicle. Other enhancements included in this update:Improvement for Engine Stop/Start (ESS) System.
18093192022-09-15. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find the following Diagnostic Trouble Codes (DTCs) have been set:P0456 - EVAP System Small Leak.If DTC P0456 is present use the wiTECH Small Leak Verification test (SLVT) to determine if a leak is present in the system. P06EF - Engine Restart Performance.
18089192022-09-15. Service bulletin. ENGINE AND ENGINE COOLING. wiTECH Small Leak Verification Test (SLVT) - P0456-EVAP SYSTEM SMALL LEAK
18-094-192019-12-16. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find one or more of the following (DTCs) have been set:P06EF - Engine Restart Performance. P0456 - EVAP System Small Leak.If DTC P0456 is present use the wiTECH Small Leak Verification test (SLVT) to determine if a leak is present in the system. P0300 - Multiple Cylinder Misfire. P0301 - Cylinder 1 Misfire. P0302 - Cylinder 2 Misfire. P0303 - Cylinder 3 Misfire. P0304 - Cylinder 4 Misfire. P0305 - Cylinder 5 Misfire. P0306 - Cylinder 6 Misfire. In addition, customers may experience the following condition:Engine will auto stop and will not auto restart or the engine will auto start and this will result in a misfire, requiring customer to shift into park and manually restart vehicle. Other enhancements included in this update:Improvement for Engine Stop/Start (ESS) System.
18-093-192019-12-16. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find the following Diagnostic Trouble Codes (DTCs) have been set:P0456 - EVAP System Small Leak.If DTC P0456 is present use the wiTECH Small Leak Verification test (SLVT) to determine if a leak is present in the system. P06EF - Engine Restart Performance.
18-089-192019-12-16. Service bulletin. FUEL SYSTEM, GASOLINE; ENGINE. wiTECH Small Leak Verification Test (SLVT) - P0456-EVAP SYSTEM SMALL LEAK

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.