E19, 20, 27, 50, 54, 57, 58, 59, 60, 61 - Meaning
Occurs when internal CPU diagnostics runs self tests and returns invalid results
Possible reason:
EMC problems (in this case, twist ignition cable around thermocouple wire several times to quench
radiated EMC emissions)
Electrode spark is tracking out somewhere but not at electrode creating unusual interference