Home18-058-26 · JEEP
JEEP

18-058-26

Manufacturer communications

Publication date
2026-06-04
Received by NHTSA
2026-06-16
NHTSA record numbers
11033868

Manufacturer summary

Original wording in English

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one of the following Diagnostic Trouble Codes (DTCs):
• P1CEA - Boost Side Evap Purge System Performance.
• 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 Customers may also experience one or more of the following:
• Engine RPM fluctuations at low vehicle speeds after extended idling.
• An ignition-off draw or battery drain condition.
• Sluggish engine performance and misfires.
• Engine knocking when the accelerator is pressed hard or quickly This bulletin involves inspecting and possibly reprogramming the PCM and Transmission Control Module (TCM) with the latest available software.

NHTSA manufacturer communications ↗

Reported code forms

Manufacturer wording

Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.

JeepP0304-00
Cylinder 4 Misfire Customers may also experience one or more of the following

NHTSA 11033868

Check vehicle applicability

A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

MakeModelModel year
JeepGRAND CHEROKEE2026
JeepGRAND CHEROKEE L2026

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