This process page covers multi-sensor EGT correlation during regen events to distinguish true thermal problems from single-sensor failures. One open or shorted EGT, an exhaust leak at a sensor boss, true DOC light-off failure, and regen fueling issues are the primary causes of regen temperature complaints. DOC or dosing components replaced because one EGT was open is the most documented misdiagnosis.

Inspect heat-zone connectors for each EGT in the chain before concluding a thermal problem. A single non-responsive sensor with all neighbors responding normally is a sensing or circuit fault — not a DOC or dosing hardware fault.

During a regen event, temperatures should rise in a logical upstream-to-downstream pattern: DOC inlet rises first, DPF outlet follows, SCR inlet follows. One sensor reading dead-low or dead-high while all neighbors respond normally is a sensing or circuit fault. All sensors failing to rise together indicates a true thermal problem — DOC light-off failure, fueling issue, or regen inhibit. Compare the non-responsive sensor against its circuit checks before any hard-part conclusions.