P06D1

An internal self-test in the control module reports a fault in its processing of the "ignition coil control" value. The module computes and cross-checks this value redundantly inside its own processor; when the results disagree, the code sets. It points to a hardware or software fault inside the module itself, not to a defect of the external sensor. Causes are an internal processor or memory fault, corrupted control-module software, or low or disturbed module supply voltage.