Some 2006-07 5.7L Dodge Ram Trucks and Durango SUVs, in addition to Jeep Grand Cherokees and Commanders (all built on or before Feb. 15, 2007), may turn on the check engine light and store one or more of the following EGR valve trouble codes in computer memory: P0404, P0405 and P0406.
If conventional EGR diagnosis doesn't reveal anything out of the ordinary, chances are the trouble codes are false and the result of software glitches in the PCM.
Reprogramming the module with updated software is the only reliable fix. Check with a dealer for the application specifics of the new calibrations.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].