05/29/2026
L5P came in for check engine light and reduced engine power. Found a large number of codes set, so we narrowed it down to the most important first. Found the whole EGR system non responsive. Went digging checking wiring and found some nasty green in the egr connector and valve itself. The terminals in the valve were too far gone to save along with the connector. We wired in a new pigtail and replaced the egr valve and got the system working again. Then chased the next set of codes for the MAF sensor which ended up being an almost broken wire at the connector. Replaced that terminal and all issues appeared to fixed. Ran it through a regeneration and then Reducant system test, lo and behold check engine light came back for DPF efficiency. Found the 4 bolt fl**ge for the exhaust missing 3 studs. Extracted the broken studs installed a new gasket and hardware and ran our tests over to verify. Passed all tests and back to work it went. It’s important to do your due diligence in verification after repairs!