Check Engine Lamp On with No Relevant Faults Stored. Intermittently, a check engine lamp (CEL) is illuminated. The CEL is not accompanied by any drivability, functionality, or emissions-related problems. In addition, no relevant faults are visible during a diagnostic session. The CEL is triggered by an erroneous fault stored in the automatic climate control unit (IHKA), which is not visible using ISTA/D.
