P26FB: EGR bypass stuck closed: restricted vacuum supply versus valve damage

A small restriction is part of the design

P26FB identifies EGR cooler bypass control stuck closed on bank 1 in this case. After the normal diagnostic procedure, FCA directs attention to the vacuum tube feeding the remote solenoid. The elbow contains a 0.6 mm brass orifice, and some airflow resistance is normal. Consequently, resistance by itself is not proof of a blocked tube, and the orifice should not be enlarged to make air pass more freely.

A blockage and a damaged valve need different remedies

If the technician confirms an actual obstruction in that orifice, the instruction is to replace the tube assembly rather than attempt to clear the blockage. A separate mechanical check assesses smooth actuator movement and the bypass valve’s internal integrity. The source uses the spring-return contact sound as one observation and directs replacement of the valve, supplied with the cooler, when that integrity check fails. These are separate findings; neither justifies replacing both assemblies without evidence.

Software is considered only after the physical checks

The March 2020 case says a false detection may remain if all specified checks find no fault, and that software improvements were under investigation at that time. It does not establish that a current update exists or that every stored P26FB is false. Preserve the original scan and ask the workshop which branch failed. Vacuum and hot-exhaust-system work should follow the exact vehicle procedure, with fitment confirmed before this historical case is applied.

Source and applicability

FCA STAR case S2018000001, March 2020, concerns P26FB and the illustrated vacuum-operated EGR cooler bypass installation. The original case lacks a full model, engine and VIN applicability table, so fitment requires vehicle-specific confirmation.

Manufacturer bulletin, page 1 · Manufacturer bulletin, page 2 · Manufacturer bulletin, page 3